diff --git a/src/fosslight_scanner/_get_input.py b/src/fosslight_scanner/_get_input.py
index 08fb904..7922601 100755
--- a/src/fosslight_scanner/_get_input.py
+++ b/src/fosslight_scanner/_get_input.py
@@ -4,11 +4,12 @@
 # SPDX-License-Identifier: Apache-2.0
 import sys
 from pip._vendor.distlib.compat import raw_input
+from typing import Tuple, List
 
 _PYTHON_VERSION = 3
 
 
-def get_input(ask_msg, default_value=""):
+def get_input(ask_msg: str, default_value: str ="") -> str:
 
     return_value = raw_input(
         ask_msg) if _PYTHON_VERSION < 3 else input(ask_msg)
@@ -18,14 +19,14 @@ def get_input(ask_msg, default_value=""):
     return return_value
 
 
-def ask_to_run(ask_msg):
+def ask_to_run(ask_msg: str) -> bool:
     return_true_item = ["y", "Y", "1"]
     return_value = raw_input(
         ask_msg) if _PYTHON_VERSION < 3 else input(ask_msg)
     return return_value in return_true_item
 
 
-def get_input_mode(_executed_path, mode_list=["all"]):
+def get_input_mode(_executed_path: str, mode_list: List[str] =["all"]) -> Tuple[str, str, str]:
     global _PYTHON_VERSION
     _PYTHON_VERSION = sys.version_info[0]
 
diff --git a/src/fosslight_scanner/_help.py b/src/fosslight_scanner/_help.py
index 27c3a29..364b10b 100644
--- a/src/fosslight_scanner/_help.py
+++ b/src/fosslight_scanner/_help.py
@@ -48,6 +48,6 @@
             -d <dependency_argument>\t    Additional arguments for running dependency analysis"""
 
 
-def print_help_msg():
+def print_help_msg() -> None:
     helpMsg = PrintHelpMsg(_HELP_MESSAGE_SCANNER)
     helpMsg.print_help_msg(True)
diff --git a/src/fosslight_scanner/_parse_setting.py b/src/fosslight_scanner/_parse_setting.py
index 83c73ad..34c6385 100644
--- a/src/fosslight_scanner/_parse_setting.py
+++ b/src/fosslight_scanner/_parse_setting.py
@@ -2,9 +2,10 @@
 # -*- coding: utf-8 -*-
 # Copyright (c) 2021 LG Electronics Inc.
 # SPDX-License-Identifier: Apache-2.0
+from typing import Tuple, List
 
 
-def parse_setting_json(data):
+def parse_setting_json(data: dict) -> Tuple[List[str], List[str], str, str, str, str, str, bool, bool, int, bool, str, bool, List[str]]:
     # check type, if invalid = init value
     mode = data.get('mode', [])
     path = data.get('path', [])
diff --git a/src/fosslight_scanner/_run_compare.py b/src/fosslight_scanner/_run_compare.py
index d547796..8abe97c 100644
--- a/src/fosslight_scanner/_run_compare.py
+++ b/src/fosslight_scanner/_run_compare.py
@@ -15,6 +15,7 @@
 import fosslight_util.constant as constant
 from fosslight_util.compare_yaml import compare_yaml
 from fosslight_util.convert_excel_to_yaml import convert_excel_to_yaml
+from typing import Tuple, Union, List, Dict, Any
 
 logger = logging.getLogger(constant.LOGGER_NAME)
 ADD = "add"
@@ -28,7 +29,7 @@
 XLSX_EXT = '.xlsx'
 
 
-def write_result_json_yaml(output_file, compared_result, file_ext):
+def write_result_json_yaml(output_file: str, compared_result: Dict[str, Any], file_ext: str) -> bool:
     ret = True
     try:
         with open(output_file, 'w') as f:
@@ -41,7 +42,7 @@ def write_result_json_yaml(output_file, compared_result, file_ext):
     return ret
 
 
-def parse_result_for_table(oi, status):
+def parse_result_for_table(oi: Dict[str, Any], status: str) -> List[str]:
     compared_row = []
     if status == ADD or status == DELETE:
         oi_ver = '' if oi['version'] == '' else f"({oi['version']})"
@@ -69,7 +70,7 @@ def parse_result_for_table(oi, status):
     return compared_row
 
 
-def get_sample_html():
+def get_sample_html() -> Union[codecs.StreamReaderWriter, str]:
     RESOURCES_DIR = 'resources'
     SAMPLE_HTML = f'bom_compare{HTML_EXT}'
     html_file = os.path.join(RESOURCES_DIR, SAMPLE_HTML)
@@ -89,7 +90,7 @@ def get_sample_html():
     return html_f
 
 
-def write_result_html(output_file, compared_result, before_f, after_f):
+def write_result_html(output_file: str, compared_result: Dict[str, Any], before_f: str, after_f: str) -> bool:
     ret = True
     html_f = get_sample_html()
     if html_f != '':
@@ -147,7 +148,7 @@ def write_result_html(output_file, compared_result, before_f, after_f):
     return ret
 
 
-def write_result_xlsx(output_file, compared_result):
+def write_result_xlsx(output_file: str, compared_result: Dict[str, Any]) -> bool:
     HEADER = ['Status', 'OSS_Before', 'License_Before', 'OSS_After', 'License_After']
     ret = True
 
@@ -176,7 +177,7 @@ def write_result_xlsx(output_file, compared_result):
     return ret
 
 
-def write_compared_result(output_file, compared_result, file_ext, before_f='', after_f=''):
+def write_compared_result(output_file: str, compared_result: Dict[str, Any], file_ext: str, before_f: str ='', after_f: str ='') -> Tuple[bool, str]:
     success = False
     if file_ext == "" or file_ext == XLSX_EXT:
         success = write_result_xlsx(output_file, compared_result)
@@ -199,7 +200,7 @@ def write_compared_result(output_file, compared_result, file_ext, before_f='', a
     return success, output_file
 
 
-def get_comparison_result_filename(output_path, output_file, output_extension, _start_time):
+def get_comparison_result_filename(output_path: str, output_file: str, output_extension: str, _start_time: str) -> str:
     result_file = ""
     compare_prefix = f"fosslight_compare_{_start_time}"
     if output_file != "":
@@ -221,7 +222,7 @@ def get_comparison_result_filename(output_path, output_file, output_extension, _
     return result_file
 
 
-def count_compared_result(compared_result):
+def count_compared_result(compared_result: Dict[str, Any]) -> None:
     comp_len = [len(compared_result[st]) for st in COMP_STATUS]
     if sum(comp_len) == 0:
         count_str = "all oss lists are the same."
@@ -231,7 +232,7 @@ def count_compared_result(compared_result):
     logger.info(f"Comparison result: {count_str}")
 
 
-def run_compare(before_f, after_f, output_path, output_file, file_ext, _start_time, _output_dir):
+def run_compare(before_f: str, after_f: str, output_path: str, output_file: str, file_ext: str, _start_time: str, _output_dir: str) -> bool:
     ret = False
     before_yaml = ''
     after_yaml = ''
diff --git a/src/fosslight_scanner/cli.py b/src/fosslight_scanner/cli.py
index 2a61c65..201198a 100644
--- a/src/fosslight_scanner/cli.py
+++ b/src/fosslight_scanner/cli.py
@@ -10,10 +10,12 @@
 from ._parse_setting import parse_setting_json
 from fosslight_util.help import print_package_version
 import os.path
+from typing import Tuple, List, Union
 
 
-def set_args(mode, path, dep_argument, output, format, link, db_url, timer,
-             raw, core, no_correction, correct_fpath, ui, setting, exclude_path):
+def set_args(mode: List[str], path: List[str], dep_argument: str, output: str, format: str, link: str, db_url: str,
+             timer: bool, raw: bool, core: int, no_correction: bool, correct_fpath: str, ui: bool, setting: str,
+             exclude_path: List[str]) -> Tuple[List[str], List[str], str, str, str, str, str, bool, bool, int, bool, str, bool, List[str]]:
     if setting and os.path.isfile(setting):
         try:
             with open(setting, 'r', encoding='utf-8') as file:
@@ -43,7 +45,7 @@ def set_args(mode, path, dep_argument, output, format, link, db_url, timer,
         raw, core, no_correction, correct_fpath, ui, exclude_path
 
 
-def main():
+def main() -> None:
     parser = ArgumentParser(description='FOSSLight Scanner', prog='fosslight_scanner', add_help=False)
     parser.add_argument('mode', nargs='*', help='source| dependency| binary| all| compare', default="")
     parser.add_argument('--path', '-p', help='Path to analyze (In compare mode, two FOSSLight reports',
diff --git a/src/fosslight_scanner/common.py b/src/fosslight_scanner/common.py
index 503cba1..ddbf1dd 100755
--- a/src/fosslight_scanner/common.py
+++ b/src/fosslight_scanner/common.py
@@ -16,6 +16,7 @@
 from fosslight_util.read_excel import read_oss_report
 from fosslight_util.output_format import write_output_file
 from fosslight_util.oss_item import OssItem
+from typing import List, Tuple, Dict, Union, Any
 
 logger = logging.getLogger(constant.LOGGER_NAME)
 SRC_SHEET = 'SRC_FL_Source'
@@ -27,7 +28,7 @@
 BIN_HIDDEN_HEADER = {'TLSH', "SHA1"}
 
 
-def copy_file(source, destination):
+def copy_file(source: str, destination: str) -> Tuple[bool, str]:
     copied_file = ""
     try:
         shutil.copy(source, destination)
@@ -42,7 +43,7 @@ def copy_file(source, destination):
         return True, copied_file
 
 
-def run_analysis(path_to_run, params, func, str_run_start, output, exe_path):
+def run_analysis(path_to_run: str, params: List[str], func: Any, str_run_start: str, output: str, exe_path: str) -> Any:
     # This function will be replaced by call_analysis_api().
     logger.info("## Start to run "+str_run_start)
     return_value = ""
@@ -62,7 +63,7 @@ def run_analysis(path_to_run, params, func, str_run_start, output, exe_path):
     return return_value
 
 
-def call_analysis_api(path_to_run, str_run_start, return_idx, func, *args, **kwargs):
+def call_analysis_api(path_to_run: str, str_run_start: str, return_idx: int, func: Any, *args: Any, **kwargs: Any) -> Tuple[bool, List[Any]]:
     # return_idx == -1 : Raw return value itself
     logger.info(f"## Start to run {str_run_start}")
     success = True
@@ -93,7 +94,7 @@ def call_analysis_api(path_to_run, str_run_start, return_idx, func, *args, **kwa
     return success, result
 
 
-def overwrite_excel(excel_file_path, oss_name, column_name='OSS Name'):
+def overwrite_excel(excel_file_path: str, oss_name: str, column_name: str ='OSS Name') -> None:
     if oss_name != "":
         try:
             files = os.listdir(excel_file_path)
@@ -115,8 +116,8 @@ def overwrite_excel(excel_file_path, oss_name, column_name='OSS Name'):
             logger.debug(f"overwrite_excel:{ex}")
 
 
-def merge_yamls(_output_dir, merge_yaml_files, final_report, remove_src_data=False,
-                default_oss_name='', default_oss_version='', url=''):
+def merge_yamls(_output_dir: str, merge_yaml_files: List[str], final_report: str, remove_src_data: bool =False,
+                default_oss_name: str ='', default_oss_version: str ='', url: str ='') -> Tuple[bool, Union[str, Exception]]:
     success = True
     err_msg = ''
 
@@ -154,7 +155,7 @@ def merge_yamls(_output_dir, merge_yaml_files, final_report, remove_src_data=Fal
     return success, err_msg
 
 
-def create_scancodejson(final_report, output_extension, ui_mode_report, src_path=""):
+def create_scancodejson(final_report: str, output_extension: str, ui_mode_report: str, src_path: str ="") ->  Tuple[bool, str]:
     success = True
     err_msg = ''
 
@@ -199,7 +200,7 @@ def create_scancodejson(final_report, output_extension, ui_mode_report, src_path
     return success, err_msg
 
 
-def correct_scanner_result(_output_dir, output_files, output_extension, exist_src, exist_bin):
+def correct_scanner_result(_output_dir: str, output_files: Dict[str, str], output_extension: str, exist_src: bool, exist_bin: bool) -> None:
     src_oss_list = []
     bin_oss_list = []
     duplicates = False
@@ -252,7 +253,7 @@ def correct_scanner_result(_output_dir, output_files, output_extension, exist_sr
     return
 
 
-def write_output_with_osslist(oss_list, output_dir, output_file, output_extension, sheetname, extended_hdr={}, hidden_hdr={}):
+def write_output_with_osslist(oss_list: List[OssItem], output_dir: str, output_file: str, output_extension: str, sheetname: str, extended_hdr: Dict[str, List[str]] ={}, hidden_hdr: set ={}) -> Tuple[bool, str]:
     new_oss_list = []
     sheet_list = {}
     sheet_list[sheetname] = []
@@ -268,7 +269,7 @@ def write_output_with_osslist(oss_list, output_dir, output_file, output_extensio
     return success, err_msg
 
 
-def get_osslist(_output_dir, output_file, output_extension, sheet_name=''):
+def get_osslist(_output_dir: str, output_file: str, output_extension: str, sheet_name: str ='') -> List[OssItem]:
     err_reason = ''
     oss_list = []
     oss_file_with_fullpath = os.path.join(_output_dir, output_file)
@@ -285,7 +286,7 @@ def get_osslist(_output_dir, output_file, output_extension, sheet_name=''):
     return oss_list
 
 
-def check_exclude_dir(oss_list):
+def check_exclude_dir(oss_list: List[OssItem]) -> List[OssItem]:
     _exclude_dirs = ["venv", "node_modules", "Pods", "Carthage"]
 
     for oss_item in oss_list:
diff --git a/src/fosslight_scanner/fosslight_scanner.py b/src/fosslight_scanner/fosslight_scanner.py
index 964810c..532eae4 100755
--- a/src/fosslight_scanner/fosslight_scanner.py
+++ b/src/fosslight_scanner/fosslight_scanner.py
@@ -30,6 +30,7 @@
 from fosslight_util.write_excel import merge_excels, merge_cover_comment
 from ._run_compare import run_compare
 from fosslight_util.cover import CoverItem
+from typing import List, Any, Tuple, Dict, Union
 fosslight_source_installed = True
 try:
     from fosslight_source.cli import run_scanners as source_analysis
@@ -48,7 +49,7 @@
 SCANNER_MODE = ["all", "compare", "reuse", "prechecker", "binary", "bin", "src", "source", "dependency", "dep"]
 
 
-def run_dependency(path_to_analyze, output_file_with_path, params="", path_to_exclude=[]):
+def run_dependency(path_to_analyze: str, output_file_with_path: str, params: str = "", path_to_exclude: List[str] = []) -> List[Any]:
     result_list = []
 
     package_manager = ""
@@ -101,12 +102,12 @@ def run_dependency(path_to_analyze, output_file_with_path, params="", path_to_ex
     return result_list
 
 
-def run_scanner(src_path, dep_arguments, output_path, keep_raw_data=False,
-                run_src=True, run_bin=True, run_dep=True, run_prechecker=False,
-                remove_src_data=True, result_log={}, output_file="",
-                output_extension="", num_cores=-1, db_url="",
-                default_oss_name="", default_oss_version="", url="",
-                correct_mode=True, correct_fpath="", ui_mode=False, path_to_exclude=[]):
+def run_scanner(src_path: str, dep_arguments: str, output_path: str, keep_raw_data: bool =False,
+                run_src: bool =True, run_bin: bool =True, run_dep: bool =True, run_prechecker: bool =False,
+                remove_src_data: bool =True, result_log: Dict[str, Any] ={}, output_file: str ="",
+                output_extension: str ="", num_cores: int =-1, db_url: str ="",
+                default_oss_name: str ="", default_oss_version: str ="", url: str ="",
+                correct_mode: bool =True, correct_fpath: str ="", ui_mode: bool =False, path_to_exclude: List[str] =[]) ->None:
     final_excel_dir = output_path
     success = True
     temp_output_fiiles = []
@@ -254,7 +255,7 @@ def run_scanner(src_path, dep_arguments, output_path, keep_raw_data=False,
         logger.debug(f"Error to remove temp files:{ex}")
 
 
-def download_source(link, out_dir):
+def download_source(link: str, out_dir: str) -> Tuple[bool, str, str, str]:
     start_time = datetime.now().strftime('%Y%m%d_%H%M%S')
     success = False
     temp_src_dir = ""
@@ -281,7 +282,7 @@ def download_source(link, out_dir):
     return success, temp_src_dir, oss_name, oss_version
 
 
-def init(output_path="", make_outdir=True):
+def init(output_path: str ="", make_outdir: bool =True) -> Tuple[bool, str, Dict[str, Any]]:
     global _output_dir, _log_file, _start_time, logger
 
     result_log = {}
@@ -305,9 +306,9 @@ def init(output_path="", make_outdir=True):
     return os.path.isdir(_output_dir), output_root_dir, result_log
 
 
-def run_main(mode_list, path_arg, dep_arguments, output_file_or_dir, file_format, url_to_analyze,
-             db_url, hide_progressbar=False, keep_raw_data=False, num_cores=-1,
-             correct_mode=True, correct_fpath="", ui_mode=False, path_to_exclude=[]):
+def run_main(mode_list: List[str], path_arg: Union[str, List[str]], dep_arguments: str, output_file_or_dir: str, file_format: str, url_to_analyze: str,
+             db_url, hide_progressbar: bool =False, keep_raw_data: bool =False, num_cores: int=-1,
+             correct_mode: bool =True, correct_fpath: str ="", ui_mode: bool =False, path_to_exclude: List[str] =[]) -> bool:
     global _executed_path, _start_time
 
     output_file = ""