In an overhung type starting electric motor, a pinion part (2c) of a movable pinion cylinder (2) is made smaller in inside diameter than a clutch inner part (2a) and a cylindrical part (2b) thereof, and a stepped part (1b) is provided between a helical spline part (1a) and the small diameter part (1c) of a rotary shaft (1) in such a manner that a very small gap is formed between the stepped part (1b) and the inner cylindrical wall of the clutch inner part (2a) of the movable pinion cylinder (2), and a very small gap is formed also between the small diameter part (1c) of the rotary shaft (1) and the inner cylindrical wall of the pinion part (2c) of the movable pinion cylinder (2). A misalignement preventing ring (11) is fitted in the clutch outer (8) of an overrunning clutch (10) to be slidable on the stepped part (16).
