| Machine Imagination Technologies | Tokyo |
| Machinepro Co., Ltd | |
| Macnica | Tokyo |
| Maebashi Institute of Technology | |
| MaeBe Co., Ltd | |
| Magna Wireless, Inc. | |
| Magnetique Co., Ltd | Tokyo |
| Mahana Corporation | |
| Mail Serve | Tokyo |
| MailMate | |
| Mainichi Future Creation Laboratory Co., Ltd | Tokyo |
| Makoto, Inc. | |
| MANA Software | Kagawa |
| Management Consulting Service Co., Ltd | Tokyo |
| Management Information Center, Inc. | Tokyo |
| Mapcom Co., Ltd | Tokyo |
| Mappin Co., Ltd | Osaka |
| MarineNet Co., Ltd | Tokyo |
| Marix Co., Ltd | |
| Markernet Co., Ltd | Tokyo |
| Marubeni IT Solutions Co., Ltd | Tokyo |
| Maruho Co., Ltd | |
| Maruishi Pharmaceutical Co., Ltd | |
| Maspro Denkoh Corporation | Aichi |
| Matrix Corporation | Tokyo |
| Matsumoto Dental University | |
| Matsumoto University | |
| Matsuri Technologies, Inc. | Tokyo |
| Matsuura Denkosha Co.,Ltd. | |
| Matsuyama University | |
| Matsuyuama Shinonome Gakuen | |
| Max | Tokyo |
| MAX-Server | Tokyo |
| MaxBrainComputerService | Hyogo |
| Maxell Ltd | Osaka |
| Maximum & Advantage Co., Ltd | Tokyo |
| Maxnet Co., Ltd | Tokyo |
| Mazin, Inc. | |
| MC Data Plus Co., Ltd | Tokyo |
| MCJ Co., Ltd | Tokyo |
| MCM Japan | |
| MCT Arianet | Tokyo |
| MEC.i Co., Ltd | |
| MECHATROLINK Members Association | Saitama |
| Med Support Systems Co., Ltd | Tokyo |
| Mediaalpha | Tokyo |
| MediaProbe Co., Ltd | Tokyo |
| Mediaseek, Inc. | Tokyo |
| Mediawars Co., Ltd | Tokyo |
| Mediba | Tokyo |