| Antenna Giken Co., Ltd | Saitama |
| Antenna House, Inc. | Tokyo |
| Antenna Technology, Inc. | Saitama |
| Anzai Medical Co., Ltd | Tokyo |
| Anzai Medical Co., Ltd | Tokyo |
| Aoi Electronics Co., Ltd | Kagawa |
| Aomori Akenohoshi Junior College | |
| Aomori Chuo Gakuin University | |
| Aomori Public University | |
| Aomori University | |
| Aomori University of Health and Welfare | |
| Aoyama Gakuin University | |
| Aoyama Startup Acceleration Center | Tokyo |
| Aozora Bank Ltd | |
| Aplix Corporation | Tokyo |
| Apollo Information System Co., Ltd | Fukushima |
| Apollocreate Co., Ltd | Tokyo |
| AppBank | Tokyo |
| Appco Group Japan Co., Ltd | Tokyo |
| Appdate Co., Ltd | Tokyo |
| Appex Corporation | Tokyo |
| Apple Doctor Co., Ltd | Tokyo |
| Apple Ginza | Tokyo |
| Apple Japan | Tokyo |
| Apple Nagoya Sakae | Aichi |
| Apple Shibuya | Tokyo |
| Apple Shinsaibashi | Osaka |
| Appleple, Inc. | Aichi |
| Appli System | Hokkaido |
| Applibot Co., Ltd | Tokyo |
| Application Products Co., Ltd | Tokyo |
| Applied Design Analysis Corporation | Tokyo |
| Applied Technology Co., Ltd | Tokyo |
| ApplyNow Co., Ltd | Tokyo |
| Appmart Co., Ltd | Tokyo |
| APProg, Inc. | |
| Appui Co., Ltd | Osaka |
| AQ | Tokyo |
| AQTIA, Inc. | |
| Aqua Moon Systems Co., Ltd | Tokyo |
| Aquabit Corporation | Tokyo |
| Arc Communications, Inc. | Tokyo |
| Arc Corporation | Osaka |
| Arcadia Knowledge Industry Co., Ltd | Tokyo |
| Archetype Corporation | Tokyo |
| Archetype Corporation | Tokyo |
| Archetype Ventures Co., Ltd | Tokyo |
| Architectural Systems, Inc. | Tokyo |
| ArcJapan, Inc. | Tokyo |
| Arcnet Ltd | Hokkaido |