Corporate Profile

Company Philosophy

Toho Earthtech develops technologies and products that benefit the public, create comfortable environments, and promote harmony with the global environment.

The Earth itself is a gigantic living organism.
We're all part of this planet, on which our existence depends.
We must love and respect one another as well as cherish the global environment for its abundant blessings. In short, we must strive to promote harmony with nature.

Based on this belief, Toho Earthtech defines its ultimate purpose through businesses that contribute to the global environment.

Corporate Profile

Incorporated March 30, 1930
Established 1957
Head Office 1450 Kurotori, Nishi-ku, Niigata City
Capital 240 million yen
Board of directors Representative Director and President Koichi Kanno
Senior Managing Director Hajime Shimizu
Executive Director Yasuhiro Hayashi
Director Tamiaki Morohashi
Director Tatsuo Tsujimoto
Director Hiroyuki Matsushita
Director (part-time) Akihiro Takahashi
Director (part-time) Koichi Isshiki
Director (part-time) Hitoshi Otani
Corporate auditor (part-time) Mitsumasa Iwase
Corporate auditor (part-time) Junya Fushida
Executive Officer Takeshi Yawata
Executive Officer Kentaro Kataoka
Executive Officer Keisuke Abe
Executive Officer Masanori Tanaka
Executive Officer Kazuhiro Honda
Number of employees 122
Business Activities
  • 1. Mining and sales of water-soluble natural gas
  • 2. Production and sales of iodine and iodine derivative products
  • 3. Maintenance and preservation work on concrete structures
  • License issued by the Minister of Land, Infrastructure, Transport and Tourism (Special Construction License 4) No. 2480
    First-Class Architect Office of Tokyo prefecture, registration approved by the Governor of Tokyo, License No. 32596
  • 4. Investigation, diagnosis, and design of concrete structures
  • 5. Manufacture and sales of adhesives for civil engineering and construction
Main Shareholders ・ Mitsubishi Gas Chemical Company, Inc.
・ Nippon Light Metal Company, Ltd.
・ ITOCHU Corporation
Main Banks ・ MUFG Bank, Ltd.
・ Development Bank of Japan
・ The Daishi Hokuetsu Bank, Ltd.
・ Mizuho Bank, Ltd.
Affiliated company TOHO, Inc.
1450 Kurotori, Nishi-ku, Niigata City, 950-1123 JAPAN
TEL: +81-25-377-2715

List of Business Locations

Head Office/Kurosaki Factory

1450 Kurotori, Nishi-ku, Niigata City, 950-1123 JAPAN

(Head Office)
General Affairs Division
TEL +81-25-377-7131 FAX +81-25-377-7580

(Kurosaki Factory)
Energy Business Division
TEL +81-25-377-2711 FAX +81-25-377-2714
Research & Development Division
TEL +81-25-377-2711 FAX +81-25-377-6820

Construction Business Division

Musashino Bldg.,
2-13-10, Shinjuku, Shinjuku-ku, Tokyo, 160-0022
TEL: +81-3-5367-2661 FAX: +81-3-5367-2666

Construction Works Department: Western Japan Group

Shin-Osaka Bldg. West Wing,
7-7-2 Nishinakajima, Yodogawa-ku, Osaka, 532-0011
TEL: +81-6-6886-8221 FAX: +81-6-6886-8228


  • 1930

    Namboku Gas Oil Co., Ltd. (predecessor company) established with capital of three million yen.

    ▲ Articles of incorporation of the Namboku Gas Oil Co., Ltd., 1930

  • 1951

    Company renamed Toho Natural Gas Co.

  • 1956

    Capital increased to 60 million yen

  • 1957

    Start of development of Ishiyama Mine, with natural gas extraction and supply

    ▲ View of the Ishiyama Mine Center in 1957

  • 1958

    Start of development of Nishikanbara Mine

  • 1959

    Capital increased to 180 million yen
    Construction works for the Nishikanbara Mine completed

    ▲ Completion ceremony for Nishikanbara Mine, 1959

  • 1964

    Completion of manufacturing plant for Toho-Dite; launch of production and sales

    ▲ Participation in preservation project for Hiroshima Peace Memorial (Genbaku Dome) with our Toho-Dite epoxy resin adhesive and repair works, 1967

  • 1965

    Registration for License from the Minister of Land, Infrastructure, Transport and Tourism under the Construction Business Act

  • 1972

    Opening of the Osaka Sales Office (current Western Japan Group, Construction Business Division)

  • 1973

    All wells at Nishikanbara Mine adopt method for maintaining water balance in soil layers using mine water injection

    ▲ First operation of the injection base at the Nishikanbara Mine, 1973

  • 1979

    Construction completed on General Office building at the Kurosaki Factory

  • 1981

    Capital increased to 240 million yen

  • 1984

    Exploratory drilling for water-soluble natural gas deposits in the Iwafune area

  • 1987

    TOHO Co., Ltd. established as wholly-owned subsidiary with capital of 20 million yen
    First production and supply of cold and hot water to Honma Corporation (Honma Kenko Land)
    Private power plant completed

  • 1988

    First production and sales of iodine

    ▲ (Top left) Iodine
    (Bottom left) Iodine drums
    (Right) Central monitoring and control system at the iodine production plant

  • 1990

    Opening of the First-Class Architect Office (Tokyo)

  • 1997

    Construction completed on the Technical Development Center and new manufacturing plant for Toho-Dite

  • 1999

    Acquisition of ISO 9002 certification (production/sales of iodine)
    Company renamed TOHO EARTHTEC, INC.

    ▲ Natural gas vehicles and gas filling station, 1999

  • 2000

    Acquisition of ISO 9001 certification (production/sales of iodine, development/design/sales of adhesives and coatings for maintenance/preservation work on civil engineering and architectural structures)

  • 2003

    Acquisition of ISO 9001 certification (structural reinforcement, aseismic reinforcement, design and application of epoxy resin injection and epoxy resin coating)

  • 2004

    Nagoya Branch Office (Nagoya Group, Construction Business Division) and Niigata Sales Office (Niigata Group, Construction Business Division) opened

  • 2006

    Joint oil exploration and development project with Teikoku Oil Co., Ltd. (now INPEX Corporation)
    First production and sales of potassium iodide

    ▲ Kurosaki Factory, 2007

  • 2009

    First production and sales of hydroiodic acid
    Hakata Branch Office (Kyushu Group, Construction Business Division) opened

  • 2010

    Acquisition of Eco-Action 21 certification (production/sales of natural gas, production/sales of iodine and iodine derivatives, production/sales of adhesives and coatings for maintenance and preservation of civil engineering and architectural buildings)

    ▲ External view of iodine production plant, 2011

  • 2012

    Sendai Office (current Tohoku Group, Construction Business Division) opened
    Acquisition of ISO 14001 certification (the following work on civil engineering structures: reinforcement work on bridges and elevated bridges (bridge columns and floor slabs), surface protection work (salt resistant coating/lining), and priming work (crack injection/cross-sectional repair); the following work on structures: structural reinforcement (columns/floors/beams), aseismic reinforcement (steel frame braces/steel sheet panels/bearing walls), and external wall renovations (crack injection/delamination injection)

  • 2014

    Construction completed on Head Office and Kurosaki Factory

  • 2020

    Closure of Niigata Group, Nagoya Group, and Kyushu Group of the Construction Business Division

  • 2021

    Partial start of water-soluble natural gas production at Nishikawa area

    ▲ 23 mining bases going online in 2021

    ▲ Six injection bases going online in 2021

  • 2023

    January: Sendai Office closed

  • 2024

    April: Partial start of iodine production at Nishikawa Plant