When a drive shaft is in a non-drive state, a second drive rotor is in a non-engaged state with a driven rotor with respect to its own rotating direction. When the drive shaft is in a drive state, a rotating force of a first drive rotor is transmitted to the second drive rotor through an urging member. As a result, a power transmitting member revolves, and a centrifugal force arranges the power transmitting member at a second clamping position. The second drive rotor receives a reaction force from a driven rotor via the power transmitting member. As a result, the second drive rotor is relatively rotated in an opposite direction to a rotating direction of the first drive rotor with respect to the first drive rotor, against an urging force of the urging member. As a result, the first drive rotor is engaged with the driven rotor with respect to its own rotating direction. Accordingly, the clutch is stably operated.