1. 合成ダイヤモンドやCBN(立方晶窒化ホウ素)輸入・販売のグローバルダイヤモンド
  2. English
  • Greeting
  • 御挨拶

Dear Valued Customers,


Since Global Diamond Co., Ltd. was establised in 1977, we have been proposed and supplied appropriate and high quality superabrasives (Diamond and CBN) imported from Russia and old Sviet block countries, North and South America, Europe, and China mainly to the Japanese valued customers to their satisfaction.

With increased supply of prodects from China in a decade, the superabrasives market has shown a drastic change in the world.

Since 1999 we have been working with major Chinese superabrasives manufactures not only to locate most reliable suppliers there but to cooperate with them for technical support and collaboration to meet the specific techinical and cost requirements from Japanese customers.

In compliance with market requirement, we have installed a new line of laboratory equipments such as "SEM", "Upright Metallurgical Microscope" and "Laser Particle Size Analyzer" in our head office. This enables more precious receiving inspection and better evaluation and services to our valued customers.

Global Diamond cordially strives for a customer centric No.1 Supplier of a wide range of Superabrasives in the market to enhance the customer's satisfaction in "Products Quality", "Cost" and "Stable Supply".




Go Kosugi


  • Company Profile
  • 会社概要
Head Office KOJIMACHI SQUARE PLAZA 5FL 2-4-11 Kojimachi Chiyoda-ku Tokyo, Japan ZIP:102-0083
TEL:(+81) 3 6256 8833
FAX:(+81) 3 6256 8831
Fukuoka Back-up Office DAINI-OKABE BILDING 9F 3-27-25 Hakataekimae Hakata-ku Fukuoka City, Fukuoka, Japan ZIP:812-0011
TEL:(+81) 92 686 8076
Thailand Contact Office Jasmine City Building, 25th floor, Sukhumvit 23, Sukhumvit Rd., Klongtoey Nua, Wattana, Bangkok 10110 
President Go Kosugi
Established November 18, 1977
Capital JPY 20,000,000
Bank References Mizuho Bank, Ltd.
MUFG Bank, Ltd.

Mono Crystalline Synthetic Diamond (Large Size)
Metal and Resin Bond Mesh Size Diamond
Metal and Resin Bond Micron Size Diamond
Polycrystalline Synthetic Diamond
Clustar Diamond(Nano Size)
CBN Powder(Mesh/Micron Size)

CVD Polycrystal Diamond

Natural Diamond for Industrial use

  • Access Map
  • アクセスマップ


Tokyo Metro, Yurakucho-line (Line Y), "KOJIMACHI"(Y15) stn. Exit1
Tokyo Metro, Hanzomon-line(Line Z), "HANZOMON"(Z05) stn. Exit3b
  • History
  • 沿革
Nov. 1977 Global Diamond Co., Ltd. was founded in Nerima-ku, Tokyo with a capital of 2.0 million yen.
Apr. 1980 Started polishing diamond for jewellery and importing jewellies
Jun. 1981 Removed head office to Marunouchi Bldg. in Chiyoda-ku, Tokyo
Oct. 1982 Started to import, export and whole sale synthetic diamond and CBN powder
Dec. 1984 Started to import, export precious and semi-precious stones.
Mar. 1987 Removed head office to Akasaka Minato-ku, Tokyo
Dec. 1988 Started to import, export diamond and CBN tools
Sep. 1990

Capital increased to 8.0 million yen

Enrolled in IDA Japan (Industrial Diamond Association of Japan)

Oct. 1995 Capital increased to 20.0 million yen
Feb. 1998 Invested to the factory of diamond and CBN in Ukraine
Sep. 1999 Started business with diamond and CBN powder manufacturers in China
Sep. 2011 Contracted sole agent agreement with Famous Diamond Industrial Co., Ltd. in China; which is worldwide leading manufacturer for resin diamond
Oct. 2014 First participated in JIMTOF 2014 (The 27th Japan Internatioinal Machine Tool Fair) in Tokyo
May 2015 Removed head office to Kojimachi Chiyoda-ku, Tokyo, for business expanding
Sep. 2017 Establish Bangkok(Thailand) Contact office
Mar. 2020 Establish Fukuoka(Kyushu,Japan) Back-up Office
  • GLOBAL DIAMOND   Please contact us by Telephone or Inquiry Form(Website).
  • Telephone Inquiry
  • tel(+81) 3 6256 8833
  • Website Inquiry
  • contactl