In a starter, a one-way clutch that transmits rotation of a motor to an output shaft has a clutch inner portion. The clutch inner portion has female helical splines in an inner periphery. Also, the clutch inner portion has a stopper at a front end of the female helical splines on the side opposite to the motor. The female helical splines engage with male helical splines formed on a rear end of the output shaft so that the output shaft is slidable in an axial direction. When the male helical splines of the output shaft are brought into contact with the stopper, relative rotation of the helical splines is restricted, thereby to stop the axial movement of the output shaft.