| 1901 |
光永星郎、日本広告株式会社を設立。4ヵ月後、電報通信社を併設。 |
| 1901 |
Hoshio Mitsunaga establishes Japan Advertising Ltd. and Telegraphic Service Co. |
| 1906 |
Telegraphic Service Co. becomes Japan Telegraphic Communication Co., Ltd. |
| 1907 |
日本電報通信社が日本広告株式会社を合併。通信・広告の併営となる。 |
| 1907 |
Japan Advertising Ltd. merges with Japan Telegraphic Communication Co., Ltd. and starts to engage in communication and advertising operations. |
| 1923 |
社長制を導入。光永星郎専務が初代社長に就任。 |
| 1933 |
本社新社屋（現・電通銀座ビル）完成。 |
| 1936 |
「電聯合併」。通信部門を同盟通信社に移譲。広告専業となる。 |
| 1936 |
Japan Telegraphic Communication Co., Ltd. relinquishes its news services department to Domei News Agency and re-launches itself as a specialized advertising agency. |
| 1940 |
光永眞三専務が第2代社長に就任。 |
| 1940 |
Shinzo Mitsunaga becomes the second President. |
| 1943 |
The Company acquires 16 companies in a move to augment its advertising agency business. Operational bases are established in Tokyo, Osaka, Nagoya and Kyushu. |
| 1945 |
上田碩三元常務が第3代社長に就任。 |
| 1945 |
Sekizo Ueda becomes the third President. |
| 1947 |
吉田秀雄常務が第4代社長に就任。 |
| 1947 |
Hideo Yoshida becomes the fourth President. |
| 1948 |
Creation of the Dentsu Advertising Awards. |
| 1949 |
Creation of the Dentsu Advertising Essay Contest for Students. |
| 1951 |
Dentsu establishes the Radio Division at its Head Office and local offices. Commercial radio broadcasting begins in Japan. |
| 1953 |
Dentsu creates the Radio and Television Division at its Head Office and local offices. Commercial television broadcasting begins. |
| 1955 |
社名を株式会社電通（DENTSU ADVERTISING LIMITED）に変更。 |
| 1955 |
Dentsu Advertising Ltd. becomes the new company name. |
| 1963 |
Tsuneji Hibino becomes the fifth President. |
| 1967 |
Completion of Tsukiji Head Office Building. |
| 1973 |
Yoshichika Nakahata becomes the sixth President. |
| 1974 |
Advertising Age : ranks Dentsu No. 1 advertising agency worldwide in terms of (calendar 1973) billings. |
| 1977 |
Hideharu Tamaru becomes the seventh President. |
| 1981 |
The company formerly known as JIMA Dentsu Advertising, Ltd. and U.S. partner Young & Rubicam's Japanese affiliate establish Dentsu Young & Rubicam as a joint venture in Tokyo. |
| 1984 |
Dentsu and U.S.-based Young & Rubicam jointly establish DYR, an international service network. |
| 1985 |
Gohei Kogure becomes the eighth President. |
| 1988 |
Advertising Age : names Dentsu the 1987 "International Agency of the Year." |
| 1989 |
Fiscal 1989 billings exceed 1 trillion yen. |
| 1993 |
Gohei Kogure becomes the first Chairman. Yutaka Narita becomes the ninth President. |
| 1995 |
Dentsu establishes five domestic regional subsidiaries. |
| 1996 |
Japan-China Advertising Education Exchange Project commences. Dentsu Tec Inc. is established. |
| 2000 |
Dentsu makes an equity investment in the Bcom3 Group. Information Services International-Dentsu, Ltd. lists its shares on the First Section of Tokyo Stock Exchange. |
| 2001 |
Dentsu lists its shares on the First Section of Tokyo Stock Exchange. |
| 2001 |
Dentsu commemorates its 100th anniversary. |
| 2002 |
ピュブリシス・グループに資本参加。 |
| 2002 |
成田社長が第2代会長に、俣木盾夫副社長が第10代社長に就任。 |
| 2002 |
経営ビジョン「価値創造パートナー」を発表。 |
| 2002 |
東京・汐留に新社屋ビル完成。 |
| 2002 |
Yutaka Narita becomes the second Chairman. |
| 2002 |
Tateo Mataki becomes the 10th President. |
| 2002 |
The Bcom3 Group merges with Publicis Groupe S.A. |
| 2002 |
Dentsu acquires a 15% stake in the newly formed group. |
| 2002-11 |
Dentsu's new Shiodome Head Office Building opens in November. |
| 2003 |
Dentsu East Japan Inc., Ad Dentsu Tokyo Inc. and Dentsu Tohoku Inc. merge, with Dentsu East Japan as the surviving company. |
| 2003 |
Geneon Entertainment Inc. and Geneon Entertainment (USA) Inc. are converted to subsidiaries. |
| 2004 |
Tateo Mataki becomes the President & CEO. |
| 2004 |
Dentsu Group initiates the UNESCO World Terakoya Movement 'kururimpa' project. |
| 2005 |
Dentsu Group obtains BS7799 certification and Information Security Management Systems (ISMS) certification. |
| 2005 |
All of Dentsu's domestic branch offices receive ISO 14001:2004 certification. |
| 2006 |
Dentsu Tec is converted to a wholly-owned subsidiary, and its shares are delisted. |
| 2007 |
俣木社長が第3代会長に、髙嶋達佳副社長が第11代社長に就任。 |
| 2007 |
Dentsu Group achieves consolidated billings (net sales) of 2 trillion yen. |
| 2007 |
Tateo Mataki becomes the third Chairman. |
| 2007 |
Tatsuyoshi Takashima becomes the eleventh President. |
| 2008 |
Dentsu establishes an internal committee for the deliberation of environment-related strategies. |
| 2008 |
Dentsu receives 'Eco-First Company' certification. |
| 2009 |
電通グループの新企業理念「Good Innovation.」を発表。 |
| 2009 |
Dentsu announces the new Dentsu Group corporate philosophy: 'Good Innovation.' |
| 2009 |
Dentsu introduces the 'Director, Member of the Board & Executive Officer' management system. |
| 2009 |
cyber communications inc. becomes a wholly-owned subsidiary. |
| 2009 |
Dentsu Announces New Medium-Term Management Plan 'Dentsu Innovation 2013'. |
| 2010 |
欧州・米州事業を管轄する「電通ネットワーク・ウエスト」を設置。 |
| 2010 |
Dentsu establishes Dentsu Digital Holdings. |
| 2010 |
Dentsu establishes Dentsu Network West. |
| 2011 |
髙嶋社長が第4代会長に、石井直専務が第12代社長に就任。 |
| 2011 |
Tatsuyoshi Takashima becomes the fourth Chairman. |
| 2011 |
Tadashi Ishii becomes the twelfth President & CEO. |
| 2012 |
「電通ネットワーク・ウエスト」を吸収統合した海外事業統括組織「電通ネットワーク」を設置。 |
| 2012 |
Dentsu establishes the Dentsu Network, an umbrella organization of the Company's agencies outside Japan. |
| 2012 |
Dentsu Network West is absorbed into the Dentsu Network. |
| 2013 |
Dentsu acquires Aegis Group plc and establishes a new global operating unit, Dentsu Aegis Network Ltd., in London. |
| 2014 |
東京オリンピック・パラリンピック競技大会組織委員会が マーケティング専任代理店として電通を指名。 |
| 2014 |
Dentsu Appointed as Marketing Agency by the Tokyo Organising Committee of the Olympic and Paralympic Games. |
| 2017 |
山本敏博常務が第13代社長に就任。 |
| 2017 |
Toshihiro Yamamoto becomes the thirteenth President & CEO. |
| 2020 |
純粋持株会社制に移行し、山本敏博が株式会社電通グループの初代社長に就任。 |
| 2020 |
株式会社電通の第14代社長に五十嵐博が就任。 |
| 2020 |
Transitioned to a new holding company structure, and Toshihiro Yamamoto became the first appointed to Dentsu Group Inc. |
| 2020 |
Hiroshi Igarashi was appointed the 14th President of Dentsu Inc. |
