Expert in large diameter steel pipe.




Since the start-up in 1957, our mission has been to satisfy our client with our steel pipe - large diameter, heavy wall, longitudinally welded tube. We keep improving our technology and quality to help our society take steps forward.

President and CEO Yuichi Hirota

Head Office

Name Osaka Tokushu Kokan Mfg.,Co.,Ltd.
Location Head office
2-8-24 Mitejima, Nishiyodogawa-ku, Osaka City, Osaka, 555-0012
Phone number +81-6-6475-3000
FAX +81-6-6475-2213
Capital 22.5 million yen
Founded 1937
Established 1957
Representative Yuichi Hirota, President and CEO

Sales Department
(contact for products/quotation)

Affiliates : O.T.K. Corporation (Sales Desk)
3-25-15 Uchihonmachi, Suita City, Osaka 564-0032

TEL. +81-6-6382-8601 FAX. +81-6-6382-1401 E-mail : corp@otk.ne.jp


1937 Hirota Masao Corporation founded, as a trader of drawn steel pipes and gas pipes
1957 Established as the Osaka Tokushu Kokan Mfg. Co., Ltd., started with the Osaka Plant as a manufacturer of welded steel pipes
1970 Shiga Plant established, 5,000t forming press installed
1981 Shiga Plant expanded, 15,000t forming press installed
1990 Sales department is wholly consigned to O.T.K.Corporation
Meritorious mention awarded from the prime minister (for contribution to the promotion of public welfare )
1991 Tokushima Plant established, 12,000t forming press installed. Letter of appreciation awarded from the governor of Tokushima (for contribution to regional welfare business activities)
1997 Osaka Plant closed, Shiga Plant succeeded the business
1998 Tokushima Plant expanded with the addition of Shop 2 and 6,000t forming press is installed
Pickling facility installed for integrated production of stainless steel pipes
2008 Automatic ultrasonic testing equipment is replaced with the brand-new digital models in Tokushima Plant
2012 Tokushima Plant acquired API5L-D certification.

Certifications and Authorizations

ISO9001(Quality management system)
API 5L (Line pipe)
API 2B (Structural steel pipe)
API 5LD (Clad steel pipe)
JIS A5525 Steel pipe piles
JIS G3444 Carbon steel tubes for general structure
JIS G3457 Arc welded carbon steel pipes
JIS G3459 Stainless steel pipe
JIS G3468 Large diameter welded stainless steel pipes
JIS G3475 Carbon steel tubes for building structure


Shiga Plant

414-1 Kitatuschiyama, Tsuchiyama-cho, Koka City, Shiga 528-0211
TEL.+81-748-66-1135 FAX. +81-748-66-0111
E-mail : shiga@otk.ne.jp

Tokushima Plant

139-13 Aza-Toyohisa-kaitaku, Toyohisa, Matsushige-cho, Itano-gun, Tokushima, 771-0213
TEL. +81-88-699-5511 FAX. +81-88-699-7555
E-mail : toku@otk.ne.jp