Rotation of a pinion is regulated by a pinion regulating claw when a starter is actuated. After the pinion engages a ring gear, the regulating claw positioned rearward the pinion regulates the return of the pinion from the ring gear. A thrust bearing including a rolling bearing positioned on the rear face of the pinion absorbs the difference between the rotational speed of the pinion and that of the regulating claw. Such a construction allows only the pinion to move axially and a magnet switch to be made compact and light.
