| AIS Co., Ltd | Tokyo |
| Aishin Co., Ltd | Tokyo |
| Aisin System Co., Ltd | Ehime |
| Aisys Co., Ltd | Tokyo |
| Aisys, Inc. | |
| Aitai net | Tokyo |
| AIVY Communications | Tokyo |
| AIxtal | |
| Ajinomoto Bio-Pharma Services | |
| Akibakan | Tokyo |
| Akita International University | |
| Akita Prefectural University | |
| Akita University | |
| Akita University - Department of Electrical and Electronic Engineering | Akita |
| Akita University of Art | |
| Akita University of Nursing and Welfare | |
| aLab Co., Ltd | Tokyo |
| ALE Co., Ltd | |
| ALE-NET | Tokyo |
| AlfaCom Ltd | Tokyo |
| Alfactory Co., Ltd | |
| Alfresa Holdings Corporation | Tokyo |
| Algae Science Japan Co., Ltd | Okinawa |
| Algo System Co., Ltd | |
| Alinco, Inc. | Osaka |
| Alive Co., Ltd | Tokyo |
| All Right Co., Ltd | Kanagawa |
| Alles Net | Tokyo |
| Allied Telesis | Tokyo |
| Allm, Inc. | |
| Allsmart Co., Ltd | Tokyo |
| Almex Technologies, Inc. | |
| Alpha Co., Ltd | Tokyo |
| Alpha Code Co., Ltd | Tokyo |
| Alpha Electronics Corporation | Tokyo |
| Alpha Link Co., Ltd | Tokyo |
| Alpha Net Co., Ltd | Tokyo |
| Alpha Systems, Inc. | Tokyo |
| Alphasting Co., Ltd | Osaka |
| Alphasystem Corporation | Yamagata |
| Alphaus, Inc. | Tokyo |
| Alpine Electronics, Inc. | Tokyo |
| Alps Alpine Co., Ltd | Tokyo |
| ALT Co., Ltd | Tokyo |
| alt, Inc. | Tokyo |
| AM Japan Co., Ltd | Tokyo |
| Amada Co., Ltd | |
| Amateras | Tokyo |
| Amaya Co., Ltd | Saitama |
| American Chamber of Commerce in Japan | |