In case one of three clutch pawls 29 protrudes outwardly from the side surface of a pawl base 76 and engages with a clutch gear 30 and the remaining two clutch pawls 29 are not yet engaged with the clutch gear 30, the peripheral portion of a deforming through hole 29D of the clutch pawl 29 engaging with the clutch gear 30 is plastically deformed and the clutch pawl 29 is deformed in a substantially L-shape while engaging with the clutch gear 30. Then, the pawl base 76 can be rotated further and the remaining two clutch pawls 29 further protrude outwardly from the side surface of the pawl base 76 and engage with the clutch gear 30.