| Blockchain App Factory | Tokyo |
| Blockchain Lock Co., Ltd | Tokyo |
| Bloom Technology Corporation | Kumamoto |
| Blue Planet-works Co., Ltd | Tokyo |
| Blue Style Co., Ltd | Shizuoka |
| BlueMeme Co., Ltd | Tokyo |
| Bonds Investment Group | Tokyo |
| BooBooClub | Tokyo |
| Booost Technologies, Inc. | |
| BOSCO Technologies, Inc. | |
| BPlats, Inc. | Tokyo |
| Brain Box Co., Ltd | Tokyo |
| Brain Corporation | Tokyo |
| Brain Magic Co., Ltd | Tokyo |
| Brain Net Co., Ltd | Kyoto |
| Brain Systems Co., Ltd | Tokyo |
| BrainNet Co., Ltd | Tokyo |
| BrainPad Co., Ltd | Tokyo |
| Brains Technology Co., Ltd | Tokyo |
| Braizon Therapeutics | |
| BrandAcademy | |
| BrandAcademy | |
| Brastel Co., Ltd | Tokyo |
| Bravesoft Co., Ltd | Tokyo |
| Bridge Co., Ltd | Tokyo |
| BrightPath Biotherapeutics Co., Ltd | |
| Brisys Co., Ltd | Tokyo |
| BroadBand Security, Inc. | Tokyo |
| Broadcasting Satellite System Corporation | Tokyo |
| Broadtech Co., Ltd | Tokyo |
| Brooks & Co., Ltd | Tokyo |
| Bros Soft | Osaka |
| Brother Industries Ltd | Aichi |
| Brycen Co., Ltd | |
| BS Conditional Access Systems Co., Ltd | Tokyo |
| BSOL Co., Ltd | Chiba |
| BTD Studio Co., Ltd | Tokyo |
| BTV Cable Television | Tokyo |
| Buildsystem Co., Ltd | Tokyo |
| Bukkyo University | |
| Bunka Fashion Graduate University | |
| Bunkyo Gakuin University | |
| Bunkyo University | |
| Bunri University | |
| Busicom | Tokyo |
| Business Associates Co., Ltd | Tokyo |
| Business Computer Co., Ltd | Chiba |
| Business Engineering Corporation | Tokyo |
| Business Link Co., Ltd | Tokyo |
| Business Search Technologies Corporation | Tokyo |