| +Automation Co., Ltd | Tokyo |
| 01Booster Co., Ltd | Tokyo |
| 01Booster, Inc. | |
| 01earth, Inc. | Osaka |
| 1-UP Studio Co., Ltd | Tokyo |
| 10X, Inc. | |
| 117net | Kanagawa |
| 12office | Tokyo |
| 17LIVE Co., Ltd | Tokyo |
| 19inch.jp | Tokyo |
| 1stBit Co., Ltd | Tokyo |
| 1x1 Co., Ltd | Osaka |
| 207 Co., Ltd | Tokyo |
| 24-7, Inc. | Tokyo |
| 2Style.net | Saitama |
| 3Films Co., Ltd | Tokyo |
| 3i Co., Ltd | Gunma |
| 3Web | Tokyo |
| 8107 | Tokyo |
| 8bit Co., Ltd | Tokyo |
| 98Factory | Aichi |
| A Touch of Tensai | Fukuoka |
| A&A Co., Ltd | Osaka |
| A&A System | Kanagawa |
| A&D Network | Tokyo |
| A-Net Co., Ltd | Tokyo |
| A-POC | Tokyo |
| A-Star Quantum Co., Ltd | Tokyo |
| A.N.Lab, Inc. | |
| A.T. Works, Inc. | Tokyo |
| Abalance | Tokyo |
| ABBALab | Tokyo |
| ABC Dream Ventures, Inc. | Osaka |
| ABC Dream Ventures, Inc. | |
| ABEJA Co., Ltd | Tokyo |
| AbelSoft Co., Ltd | Saitama |
| Abies Ventures | Tokyo |
| ABIT Co., Ltd | Tokyo |
| ABKSS Co., Ltd | Tokyo |
| ABLE Computer Giken Co., Ltd | Hokkaido |
| Ablenet | Tokyo |
| ABLIC, Inc. | |
| ABsystem | Tokyo |
| AC Technologies Co., Ltd | Kanagawa |
| Academic Newtown Community Cable Service | Ibaraki |
| Accela Technology Corporation | Tokyo |
| Access Co., Ltd | Tokyo |
| Access Intelligent Co., Ltd | Kumamoto |
| AccuRna Co., Ltd | Tokyo |
| aceRNA Technologies, Inc. | |