COMPANY PROFILE

CEO MESSAGE

The accident at the Fukushima Daiichi Nuclear Power Plant was a profound event that called into question the very relationship between technology and society. We believe it is not the next generation, but those of us living today, who bear the responsibility to face these challenges directly.

In the extreme conditions of nuclear decommissioning, there are many situations where conventional technologies cannot cope—especially in terms of radiation resistance. It was to address these very challenges that we began working with diamond semiconductors. Today, as a first step toward real-world application, we are constructing the world’s first diamond semiconductor manufacturing facility in Okuma, Fukushima. We chose to carry the name Okuma in both our company and our pilot line’s location because we believe in building hope from the very place where the Fukushima Daiichi Nuclear Power Plant stands.

Our vision extends beyond applications in nuclear power. We believe this technology holds true significance only when it is applied to foundational industries that support the future—such as space, defense, and next-generation communications. What began in Fukushima has the potential to grow into a force that supports a safer and more sustainable society. We are committed to turning that possibility into reality.

Bringing the industries of the next era from Fukushima to the world—this is the challenge we have embraced.

Ookuma Diamond Device Co., Ltd.
CEO
Naohisa Hoshikawa

COMPANY
PROFILE

Company NameOokuma Diamond Device Co., Ltd.
RepresentativeNaohisa Hoshikawa
Business DomainResearch and Development of Diamond Semiconductors
EstablishedMarch 1, 2022
LocationHead Office
Hokudai Business Spring, Kita 21-jo, Nishi 12-chome 2, Kita-ku, Sapporo, Hokkaido 001-0021, Japan

Sapporo Office*
Collabo Hokkaido E Room, Kita 21-jo Nishi 12-chome, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
(*Please visit this location when coming to our company.)
Google Maps
Ookuma Diamond Device First Plant
94-8 Aza-Hara, Oaza-Shimonogami, Okuma-machi, Futaba-gun, Fukushima, 979-1308, Japan
(located within the Okuma Central Industrial Zone)

Fukushima Branch
230 Aza-Shimizu, Oaza-Shimonogami, Okuma-machi, Futaba-gun, Fukushima, 979-1308, Japan
Google Maps
Tsukuba Laboratory
1-1-1 Umezono, Tsukuba City, Ibaraki, 305-0045, Japan
(*located inside the National Institute of Advanced Industrial Science and Technology)
Google Maps
Banking PartnersMizuho Bank, Ltd.
Sumitomo Mitsui Banking Corporation
Sumitomo Mitsui Trust Bank, Limited
Hokkaido Bank, Ltd.
Hokuriku Bank, Ltd.
Toho Bank, Ltd.
THE 77 BANK, Ltd.
Joyo Bank, Ltd.
Major ShareholdersGlobis Capital Partners
Coral Capital, Inc.
Green Co-Invest I, L.P.
Astart Inc.
Japan Post Bank Spiral Regional Innovation No.1 Investment L.P.
MS&AD Ventures Co., Ltd.
SMBC Venture Capital, Ltd.
FFG Venture Business Partners Co., Ltd.
Hokuhoku Capital Co., Ltd.
SBI Neo Investment Inc.
Research PartnersHokkaido University
National Institute of Advanced Industrial Science and Technology (AIST)
National Institute for Materials Science (NIMS)
High Energy Accelerator Research Organization (KEK)
Tohoku University
Nagoya University
Others
Awards and RecognitionsSeptember 2023: 2nd Place in “Real Tech Catapult” at ICC KYOTO 2023
February 2024: Selected as a “J-Startup HOKKAIDO” Company (Ministry of Economy, Trade and Industry, METI)
March 2024: Special Jury Prize at the “GX Startup & Researcher Pitch Contest” (METI)
April 2024: Award Winner at “RISING STAR Meet-up 2024” (Forbes JAPAN)
August 2024: Selected for “Forbes Asia 100 To Watch 2024” (Forbes)
September 2024: Featured in “100 Amazing Ventures 2024” (Weekly Toyo Keizai)
February 2025: Grand Prize in the Startup Category at the 6th IP BASE AWARD (Japan Patent Office)
March 2025: Winner of EY Innovative Startup 2025 (Ernst & Young ShinNihon LLC)
March 2025: Encouragement Award at the “Entrepreneur Awards of the North” (Sapporo Chamber of Commerce and Industry)
March 2025: Selected for “J-Startup (5th Round)” (METI)

PILOT PLANT

The world’s first diamond semiconductor fabrication plant is under construction in Okuma, Futaba District, Fukushima, the site of the Fukushima Daiichi Nuclear Power Plant. Completion is scheduled for 2026.