| Bank of Fukuoka Ltd | |
| Bank of Iwate Ltd | |
| Bank of Japan | Tokyo |
| Bank of Kyoto Ltd | Kyoto |
| Bank of Okinawa Ltd | |
| Bank of Saga Ltd | |
| BANQ Corporation | Tokyo |
| Barrett Group Co., Ltd | Tokyo |
| BayHub Technology Co., Ltd | Tokyo |
| BBS Kinmei Co., Ltd | Ishikawa |
| Be-Tec Co., Ltd | Tokyo |
| Beans Computer School | Osaka |
| Beat Tech Co., Ltd | Tokyo |
| BeauPlan Co. | Osaka |
| Beauty and Create Co., Ltd | Tokyo |
| beBit, Inc. | Tokyo |
| Begi.net, Inc. | |
| Being Co., Ltd | Mie |
| Bekkoame//Internet | Tokyo |
| Bell Data, Inc. | |
| Bell Software, Inc. | Tokyo |
| Bell-Park Co., Ltd | Tokyo |
| BenQ Japan | Tokyo |
| Beppu Mzobe Gakuen College | |
| Beppu University | |
| Best Kendi Co., Ltd | Tokyo |
| BestAbility Co., Ltd | Tokyo |
| Bewith Enterprise Ltd | Tokyo |
| Beyond Next Ventures Co., Ltd | Tokyo |
| Big Bang System Corporation | Tokyo |
| Big Country Co., Ltd | Tokyo |
| BiG-NET | Tokyo |
| Biglobe, Inc. | Tokyo |
| Bigvan, Inc. | Tokyo |
| Billing System Corporation | Tokyo |
| Bio Academia Co., Ltd | Osaka |
| BioComo | |
| Biocomo Co., Ltd | Mie |
| BioMimetics Sympathies, Inc. | |
| BioRuby | Tokyo |
| Bios Co., Ltd | Tokyo |
| BIOSYS Corporation | Tokyo |
| Bioworks Co., Ltd | Kyoto |
| Bis-StuDio | Tokyo |
| bitA Co., Ltd | Tokyo |
| bitBiome Co., Ltd | Tokyo |
| Bitcross Co., Ltd | Tokyo |
| bitFlyer, Inc. | |
| Bitforest Co., Ltd | Tokyo |
| Bitkey Co., Ltd | Tokyo |