1. 8 Group Companies
  2. Group Companies (in Japan)

Major Group Companies (in Japan)

* As of the end of March 2021 (the name of the representative and the current officers as of July 1, 2021)
* The websites of the domestic group companies are Japanese domestic sites (in Japanese)


Name of the representative Shuji Kurokawa
Head Office location Sumitomo Fudosan Sarugakucho Building, 2-8-8, Kanda-sarugakucho, Chiyoda-ku, Tokyo, Japan
Telephone number 81-3-3295-8860
Website www.obayashi-road.co.jp
Date of incorporation August 26, 1933
Capital JPY6,293,000,000
Description of business Road work, paving work, water supply and sewerage system work, manufacturing and sales of asphalt mixtures, etc.
Net sales JPY100,059,000,000
Employee headcount 1,142

This company was established through joint capital investment by Obayashi Corporation and other companies in August 1933 under the trade name of Toyo Hoso Kabushiki Kaisha. Initially the company established a factory in Yokohama, and became involved in manufacturing and sales of asphalt emulsion, and paving work contracting. During the war, the company went out of business temporarily, but after the war it received orders for work related to the Allied Occupation forces, government agency work, paving work on the premises of private sector factories, etc., and the business got back on track.

Upon entering Japan’s high-growth period, the road construction and improvement business grew rapidly together with the progress of motorization, and this company also followed the same path. In February 1967, the company name was changed from Toyo Hoso Kabushiki Kaisha to the current OBAYASHI ROAD CORPORATION. The company aimed to ensure greater trust and expand the business by clarifying the cooperative relationship with Obayashi Corporation. In April 1971, the company was listed on the Second Section of the Tokyo Stock Exchange and in February 1973 it achieved listing on the First Section of the Tokyo Stock Exchange.

Subsequently, the company experienced many tough situations, such as the oil shock, the period of winter-like hardship for the construction industry, the bubble economy and its collapse, the Heisei recession, and the contraction of the construction market, but it endeavored to rationalize its management and has overcome all of those situations.

In September 2017, the listing on the First Section of the Tokyo Stock Exchange was removed as a consequence of the company being made a wholly owned group subsidiary by Obayashi Corporation.

In recent years, the company has been actively engaged in maintenance and updating work due to all kinds of infrastructure becoming increasingly decrepit, and in recovery work arising from increasingly severe natural disasters, and it is also working on productivity increases utilizing IT technologies, and construction, product manufacturing, etc. which take into consideration global environmental conservation.


Name of the representative Masato Yanou
Head Office location Sumitomo Ichigaya Building, 1-1, Ichigaya-honmuracho, Shinjuku-Ku, Tokyo, Japan
Telephone number 81-3-5261-3410
Website www.naigai-technos.co.jp
Date of incorporation October 1, 1931
Capital JPY150,000,000
Description of business Woodworking, complete interiors, seismic strengthening work, construction materials sales
Net sales JPY91,637,000,000
Employee headcount 149

The history of this company goes back to a lumber mill launched shortly after the founding of Obayashi Corporation, but when it changed its name to Obayashi Engineering Center in 1922, it had already gained an established reputation in the artistic woodworking field, making joinery, fixtures, furniture, etc. When NAIGAI MOKUZAI KOGEI CO., LTD was established in October 1931, it used its first-grade facilities and outstanding technologies to undertake a series of interior projects for buildings which are some of the most celebrated in the history of architecture, leading the woodworking industry and establishing the company's fame and base of operations. Under the war regime, Naigai mainly fitted out military ships and manufactured parts for wooden aircraft. After WWII, in 1946, the company changed its name to NAIGAI MOKUZAI KOGYO CO., LTD. The company saw a large rise in woodworking and interior projects as the economy recovered and showed rapid growth and construction of all kinds of buildings started up in earnest. In April 1993, the company name was changed to the current NAIGAI TECHNOS CORPORATION. The company has honed traditional technologies while also actively working to conduct research and development of new construction methods and new interior materials, and it has undertaken interior and exterior work on buildings with a broad range of applications, from office buildings and hotels to art and shrine and temple architecture, etc.

In April 1998, a trading business was newly launched in order to maximize the purchasing advantages of the group, and the company is handling a wide range of fields from major construction materials and heavy work machinery in the construction field to the fields of fire prevention and earthquake-resistant interior and exterior architectural materials.

In April 2021, the company acquired the shares of TUKUSI CORPORATION, a company specializing in wooden construction and possessing a history and brand for more than 135 years since its founding. It is aiming to further expand its business operations, and to promote the Obayashi Group’s initiatives for architecture with wooden materials.


Name of the representative Katsunori Hanato
Head Office location Sumitomoshoji Nishikicho Building, 1-6, Kanda-nishikicho, Chiyoda-ku, Tokyo, Japan
Telephone number 81-3-5281-8311
Website www.obayashi-f.co.jp
Date of incorporation October 1, 1963
Capital JPY50,000,000
Description of business Building management business (facilities management, cleaning, security, condominium management, owner agency operations, etc.)
Construction business (all kinds of operations related to construction work, including new construction work, renewal work fixtures and fittings delivery, etc.)
Business support business, operation business
Net sales JPY27,858,000,000
Employee headcount 785

The predecessor of this company was TOYO BUILDING SERVICE CORPORATION established in October 1963. Its business objectives were facilities management of buildings and all other kinds of facilities constructed by Obayashi Corporation, building and repairs work, cleaning work, safety and security contracting, etc. Its main business area was the Kansai region, but in March 1986 it split off an independent Tokyo Branch for the purpose of further expanding its business in the East Japan region, and established OAK BUILDING SERVICE CORPORATION. In July 2005, in order to strengthen its marketing capability by putting in place a structure that could cover all of Japan with one company to handle the nationwide increase in building construction, the company integrated TOYO BUILDING SERVICE CORPORATION and OAK BUILDING SERVICE CORPORATION and changed the company name to the current Obayashi Facilities Corporation.

Currently, based on the abundant achievements and know-how of the Obayashi Group, it is developing its business centered on the Building Construction Business, including the comprehensive maintenance and management business for all kinds of building facilities, new construction and renovation work, and building diagnostics. Furthermore, it is expanding its operations to operate a business support business which accepts contracts for personnel and general affairs management operations, etc. such as payroll accounting and benefits packages as the shared service center of the Obayashi Group, and an operation management business which accepts contracts for the accounting, finance, and labor management operations, etc. of renewable energy business companies and PFI business companies.


Name of the representative Kimiyoshi Sato
Head Office location Sumitomo Fudosan Kayabacho Building, 1-16-3, Shinkawa, Chuo-ku, Tokyo, Japan
Telephone number 81-3-3553-2911
Website www.oaksetsubi.co.jp
Date of incorporation November 30, 1963
Capital JPY300,000,000
Description of business General architectural facilities construction work (air conditioning, sanitation, and electricity), and production facilities construction work for clean rooms, plants, etc.
Net sales JPY20,309,000,000
Employee headcount 248

The predecessor of this company was Tokyo Cooling and Heating Industries Corporation, which was established in November 1963 with capital investment by Toshiba Corporation, and engaged in sales and installation of air-conditioning equipment. In 1980 the similar group subsidiaries in regions throughout Japan were integrated, and TOSHIBA AIR CONDITIONING CO., LTD was launched as a facilities work company operating on a nationwide scale.

Since then, it has broadly expanded its business as a comprehensive facilities work company accepting contracts for integrated processes from design to construction for general architectural facilities, etc., with a focus on special facilities work related to Toshiba’s semiconductor factories.

On July 1, 2003, Obayashi Corporation acquired all of the shares of this company from Toshiba with the objective of strengthening its facilities work, and it became a group company with its company name becoming the current Oak Setsubi Corporation.

Since its founding, with the design, construction, and renewal of air-conditioning facilities and sanitary facilities as the core of its business, it has been building ideal “environments” with reliable technological capabilities, from the secure, safe, and comfortable environments of skyscrapers, government buildings, hospitals, etc. to advanced production environments such as the clean rooms of industrial facilities including factories and laboratories. Furthermore, in recent years, it has been endeavoring to meet a variety of needs of customers, such as energy savings and resource savings, and further improvement in its business performance is expected going forward.


Name of the representative Motoo Hiruma
Head Office location Kojimachi Building, 3-3-6, Kudan-minami, Chiyoda-ku, Tokyo, Japan
Telephone number 81-3-3511-7520
Website www.osre.co.jp/
Date of incorporation January 17, 1955
Capital JPY6,170,000,000
Description of business Real estate business, business management of buildings, non-life insurance agency business, etc.
Net sales JPY32,087,000,000
Employee headcount 177

The predecessor of this company was NANIWA REAL ESTATE CORPORATION established in January 1955 for the purpose of running some of the real estate operations of Obayashi Corporation. Its main businesses were the ownership, purchase and sale, lease, and brokerage of real estate, and a non-life insurance agency business. Subsequently, it actively developed a business as a developer, including development and sales of residential land and urban redevelopment. In 1970, it changed its company name to Obayashi Real Estate Corporation to reflect the expansion of its business scale and business region. After that, the company broadly expanded its business to urban development centered on its leasing business, the design and construction of houses, etc.

In October 2014, Obayashi Real Estate Corporation merged with Seiwa Real Estate Co., Ltd., which had been running a wide range of businesses including the condominium property sales and stand-alone house property sales businesses, renovations and brokerage, etc. primarily in the Kansai region and the Tokyo metropolitan area since its founding in 1953, and Obayashi-Shinseiwa Real Estate Corporation was born.

As a comprehensive real estate company responsible for the core of the real estate development business of Obayashi Group, it is aiming to be a company that continues to be trusted by its customers through the creation of spaces in which people live, grow, and work.


Name of the representative Koji Furuse
Head Office location Tennoz Ocean Square, 2-2-20, Higashi-shinagawa, Shinagawa-ku, Tokyo, Japan
Telephone number 81-3-6844-3900
Website www.oakis.co.jp
Date of incorporation January 27, 1986
Capital JPY45,000,000
Description of business Development and sales of computer software, etc.
Net sales JPY8,244,000,000
Employee headcount 212

The predecessor of this company was Oak System Corporation established in January 1986. Its purposes were the development and sales of computer software which carried out technical calculations and administrative calculations concerning construction, and sales, etc. of design and drafting support systems and electronic devices.

In October 2002, it merged with CPC Corporation, which was offering a CAD input service and server and LAN construction and operation services, and in November the same year the company name was changed to the current Oak Information System Co. Due to this merger, the company had a structure which could provide comprehensive information services from system development to operation and maintenance.

It is also actively working on in-house development of software, and it began selling the information leakage prevention system NetEvidence in 2004 and the file encryption software CyberCrypt in 2005. In 2015, it began service provision of Nippo 365(*1), a cloud-based system offering centralized management of construction sites from the arrangement of workers to man-hour counting and attendance counting, and the following year, 2016, it began service provision of Nippo 365 for Security(*2).

It is working hard to contribute to productivity increases and new value creation through the upgrading of all aspects of ICT and furthermore to contribute to the building of a strong management foundation for the Obayashi Group overall.

  1. Nippo 365: A daily report by which HR managers and supervisors can examine how employees are spending their working hours.
  2. Nippo 365 for Security: Security service control system
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