| Mitsui Knowledge Industry Co., Ltd | Tokyo |
| Mitsui Sumitomo Insurance Venture Capital Co., Ltd | |
| Mitsui Zosen Systems Research, Inc. | Tokyo |
| Mitsumi Electronic Co., Ltd | Tokyo |
| Mix Wave, Inc. | |
| Mixense Co., Ltd | Tokyo |
| Mixhost | |
| Mixi | |
| Miyagi Gakuin Women's University | |
| Miyagi University | |
| Miyagi University of Education | |
| Miyazaki Municipal University | |
| Miyazaki Prefectural Nursing University | |
| Miyazaki Sangyo-keiei University | |
| Miyazaki University - Department of Computer Science and Systems Engineering | Miyazaki |
| Miyoshi Electronics Corporation | Hyogo |
| Mizuho Capital Co., Ltd | Tokyo |
| Mizuho Research & Technologies Ltd | Tokyo |
| MMM Internet | Tokyo |
| MMTR | Tokyo |
| MNET, LLC | |
| Mobile Factory Co., Ltd | Tokyo |
| Mobile Internet Capital Co., Ltd | Tokyo |
| Mobile Monday Tokyo | Tokyo |
| Mobile Support Co., Ltd | Tokyo |
| Mochida Pharmaceutical Co., Ltd | |
| Mode Guken | |
| Moeruze Co., Ltd | Tokyo |
| Moi Corporation | |
| Momotaro-Gene Co., Ltd | Okayama |
| Monaca | Tokyo |
| Monex Ventures Co., Ltd | Tokyo |
| Money Forward, Inc. | |
| Moneytree Co., Ltd | Tokyo |
| Monolith | |
| Monstarlab | |
| Moobon Co., Ltd | Tokyo |
| Mooter | Tokyo |
| More Joyful Innovation Co., Ltd | Tokyo |
| Morinomiya University of Medical Sciences | |
| Moswell Co., Ltd | Kanagawa |
| Motion System Corporation | |
| Motoup Co., Ltd | Tokyo |
| Moula, Inc. | Kanagawa |
| Mov Co., Ltd | Tokyo |
| Move Tech Co., Ltd | Shiga |
| MOVO | Tokyo |
| Moyosoft | Hyogo |
| MTechno Co., Ltd | Tokyo |
| MTT Corporation | |