An output shaft of a wiper motor is connected to a wiper to transmit a rotational force of the wiper motor to the wiper to reciprocally swing the wiper between an upper return position and a lower return position in response to forward and backward rotations of the output shaft upon energization of the wiper motor. When the wiper is stopped at the lower return position, the control unit executes a stop position holding control operation in such a manner that the control unit controls a rotational direction of the wiper motor to apply a rotational force to the wiper in a downward direction and controls the rotational force of the wiper motor based on a speed of the vehicle to substantially maintain the wiper at the lower return position.