We are a company that contributes to the creation of a sustainable society by providing technical services of electrical, mechanical and refrigeration field and supporting important infrastructure and logistics businesses that are indispensable for people's lives and corporate activities.
Boltech Co.,Ltd. is a group of engineers 100% capitalized by NYK, with Yokohama Denko Electric Co., Ltd., established in 1966, as the surviving company, and in 2008, Daito Marine Engineering Co., Ltd. and Toyo Reefer Maintenance Co., Ltd. merged into the company.
For half a century since our founding, we have been close to our customers' needs and supported by their trust, refining our on-site technical capabilities through inspection, maintenance, operation and adjustment of onshore power generation, distribution facilities and marine equipment. And we have also cultivated the design, manufacturing and construction technology of electric control system.
We will continue to be a company that can respond to the changing demands of society while boldly taking on the challenge of new technological innovations and focusing on training field engineers who will lead the next generation. We look forward to your continued support and encouragement.


Growing with customers while creating value through our business


  • ● We provide the highest value products and services that reflect the needs of our customers.
  • ● We are delighted to provide services that truly please our customers.
  • ● Work earnestly with sincerity, creativity, and enthusiasm.
  • ● Continue to have transparency and norms.
  • ● Continue to have the ambition to challenge.

We will endeavor to gain further trust and satisfaction through these policies.
We look forward to your continued support and guidance in the future.

President and CEO

Kazumasa Okazaki

Corporate Profile

Corporate Name Boltech Co., Ltd.
Head Office 2-8-13 Okano, Nishi-ku, Yokohama
President and CEO Kazumasa Okazaki
Main activities Sales of products and services for marine vessel and plant
Founded September 18, 1966
Capital 30 million yen
Stockholder Nippon Yusen Kabushiki Kaisha
Total assets 2.47 billion yen (fiscal year ending March 2022)
Number of Employees 149
Member organization The Ship's Electric Installation Contractors' Association of Japan
Yokohama Naka Corporation Association
The Kobe Chamber of Commerce& Industry
Main bank MUFG Bank, Ltd.
Mitsubishi UFJ Trust and Banking Corporation
The Bank of Yokohama,Ltd.
Construction license General Construction Industry Minister of Land, Infrastructure, Transport and Tourism permission (general 21) No. 23061
General Building, Scaffolding, Earthwork and Concrete, Electrical , Plumbing , Steel Structure , Machine and Equipment Installation
Acquisition certification ISO9001: 2015 (Electricity Division / Machinery Division)

Quality Policy

Boltech Co., Ltd. has the following as our policy, Seven Stars, in all of our activities.

  • ★. Provide high value-added products and services to customers, which is the purpose of quality activities.
  • ★. We give top priority to improving customer satisfaction and ensuring quality.
  • ★. Providing the required quality at the optimum cost.
  • ★. We have sincerity, creativity, enthusiasm, and norms, and we value and respect the demands of our customers and society.
  • ★. The Highest-Quality Service The goal is to be recognized as The Highest-Quality Service Provider.
  • ★. Educate, train and motivate QMS for all employees.
  • ★. Make effective use of QMS, review it, and strive for continuous improvement.

June 17, 2022

President and CEO

Kazumasa Okazaki

Organization chart


April 1, 2024

List of qualified persons (main qualifications only)

Jurisdiction agency Qualification Number of people
Ministry of Internal Affairs and Communications Fire Defense Equipment Officer (Class A / Class B) 6
Certified Hazardous Material Handling Supervisor 25
Ministry of Health, Labour and Welfare Health officer’s license(Class-1) 6
Boiler expert’s license(Class-2) 13
Ministry of Economy, Trade and Industry Chief electrical engineer(class-3) 2
First-type electrical work engineer 8
2nd-type electrical work engineer 24
Ministry of Land, Infrastructure, Transport and Tourism First-Class (2nd-Class) Electric Works Execution Manager 4
Certificate of qualification for managing engineer 4
Fire and Disaster Management Agency Inspector of the Fire Protection Equipment and System 8
Battery Association of Japan Qualified person for maintenance of storage battery equipment 9
Qualified person for maintenance of storage battery equipment Private power generation equipment specialist engineer 40
The Ship’s Electric Installation Contractors’ Association of Japan Private power generation equipment specialist engineer 27
Chief Ship Electrical Engineer 6
Manager of Ship Electrical Engineer 3
The Japanese Society for Non-destructive Inspection Non-destructive test technician (PT penetrant inspection) 11

April, 2023

List of business establishments

Head office

2-8-13 Okano, Nishi-ku, Yokohama-shi, Kanagawa
Representative TEL: +81-45-290-6085
Electrical Division FAX: +81-45-290-3305
General Affairs and Accounting Department FAX: +81-45-290-3317

5 minutes walk from Hiranumabashi Station on the Sotetsu Line

Yokohama office

1-2-2 Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa
Technical Group & General Affairs Group TEL: +81-45-461-6971 FAX: +81-45-453-2868
Reefer Group TEL: +81-45-900-7771 FAX: +81-45-440-5098
Sales group TEL: +81-45-900-7733 FAX: +81-45-440-5098

7 minutes walk from Koyasu Station on the Keikyu Line

Kobe office

1-2-3 Nishidemachi, Hyogo-ku, Kobe City, Hyogo Prefecture
Electrical Division TEL: +81-78-651-6031 FAX: +81-78-671-7821
Engine & Machinery Division TEL: +81-78-651-2727 FAX: +81-78-681-1386

15 minutes walk from Kobe Station on the JR Tokaido Line