A center case has a force-receiving wall and a fixed wall, and is rigidly fixed in a starter. A gear-forming section is coaxially arranged with the center case, and has a forcing wall and a movable wall on the side of the center case. A cushion member is elastically received between the force-receiving wall of the center case and the forcing wall of the gear-forming section. The fixed wall of the center case and the movable wall of the gear-forming section are arranged to have a gap, and oppose each other. When an excessive torque works on the gear-forming section via an internal gear, the cushion member absorbs an impact force to move the movable wall by a predetermined distance. In this case, the movable wall contacts the fixed wall so that a compression rate of the cushion member can be restricted.