Starter having small diameter front housing for installation from transmission side

In a starter, a front side bearing is provided between a one-way clutch and a pinion combined at a front end portion of a pinion tube. A housing supporting the pinion tube through the bearing has a housing small diameter portion where the inner diameter of the housing is set smaller than the outer diameter of the one-way clutch, between the bearing and a maximum advanced position of the one-way clutch. A housing front portion of the housing is formed into a cylindrical shape ahead of a attachment face which opposes to an engine side. The outer diameter of the front portion is gradually increased from the front end toward the attachment face. In this structure, the starter is installed from a transmission side without interfering the front portion of the housing with a transmission case.