PURPOSE: To improve engaging performance of a pinion to the ring gear and reduce the capacity of an electromagnetic switch by movably composing the lower end part of a shift lever and the arm part of an interlocking body, engaged with the lower end part, in an axis direction in a reduction gear.

CONSTITUTION: The electrification of an electromagnetic switch 34 causes the absorption of a plunger 37 to rotate a shift lever 44 in an anticlockwise direction with a hook 43. This engages the lower end part 44a of the shift lever 44 with the end part of the arm part 64b of an interlocking body 64 to forward move the end part in an axis direction. Consequently an output shaft 60 is advanced to engage a pinion 61 with a ring gear. Concurrently the armature shaft 53 of a D.C. motor 51 is rotated and deceleratedly rotated with a toothed wheel reduction gear 70, and rotation is transmitted to the output shaft 60 via an overrunning clutch 80. The starting of an engine causes the turning-off of the electromagnetic switch 34 to rotate the shift lever 44 to a retreat side. As a result, the output shaft 60 is retreated with a return spring 87 to be caught at a returned position with a bearing 77 via the pinion 61 and the overruning clutch 80.