A clutch operation mechanism wherein when a clutch is disengaged and engaged by manual operation or by operation of an actuator the one operation does not affect the other operation. The clutch operation mechanism includes a lever side lost mechanism which is disposed between a clutch lever and a turn-operating force transmitting member for interrupting, from the clutch lever side, an operated-force applied from the turn-operating force transmitting member by driving the electric motor when the clutch lever is not operated. A motor side lost mechanism is disposed between the electric motor and the turn-operating force transmitting member and interrupts, from the side of the electric motor, the operated-force applied from the turn-operating force transmitting member by operating the clutch lever when the electric motor is not operated.