Abstract: A starter motor for an internal combustion engine includes a shaft rotated by an electric motor, a pinion gear wheel carried by the shaft the gear wheel being rotated with the shaft and axially movable relative thereto between an operative position and a rest position, and an electro-magnet for moving the pinion from its rest position to its operative position. The electro-magnet includes an armature which is coupled to the pinion gear wheel, and which is guided for movement parallel to the shaft. First and second electro-magnet poles are spaced apart around the shaft and are spaced from the armature in the rest position of the armature in the direction of movement of the armature.