In case one of three clutch pawls protrudes outwardly from the side surface of a pawl base and engages with a clutch gear and the remaining two clutch pawls are not yet engaged with the clutch gear, the peripheral portion of a deforming through hole of the clutch pawl engaging with the clutch gear is plastically deformed and the clutch pawl is deformed in a substantially L-shape while engaging with the clutch gear. Then, the pawl base can be rotated further and the remaining two clutch pawls further protrude outwardly from the side surface of the pawl base and engage with the clutch gear.