Although it now belongs to Keio Group, it was originally a bus section of Ome Electric Railway Co. (present JR Ōme Line).

Okutama Shinkō is the company which Ome Electric Railway Co. established in 1928 by setting development of an area along the railroad line as the main purpose.

Ome Electric Railway purchased the Okutama Jidōsha in 1930, and it extended to Hikawa (Oku-Tama Station) in August of the same year.

Tama bus was split up by whole ownership and change of jurisdiction and commission of operation of an unprofitable route were started on April 1, 1999.

[2] Although Tama bus which business was transferred remains as a company, and will concentrate on enterprises, such as lease, management, etc.