A pedal actuator support bracket (61C) is provided at a front end portion of a frame (11) supported at a driver's seat of a vehicle. An actuator housing (78) is provided so that a base end side of the actuator housing (78) is supported by the pedal actuator support bracket (61C) so as to be able to pivot upward and downward relative to the pedal actuator support bracket (61C). A rack shaft (80) protrudes from a top end side of the actuator housing (78) and moves forward and backward along a longitudinal direction of the actuator housing (78). A pivotal plate (87) is connected to a top end of the rack shaft (80) so as to be able to pivot upward and downward and placed on a pressing surface of a clutch pedal (47) so as to overlap this pressing surface and fixed to the clutch pedal (47).