A motor case (31) in which a stationary portion (35) is fixed, and a gear case (41) in which a gear mechanism (SD) is accommodated are made of aluminium, most heat generated from the stationary portion (35) at the time of actuation of a brushless wiper motor (20) can be directly dissipated outside from the motor case (31). That is, compared with conventional technique, heat transmitted to the motor case (31) can be efficiently dissipated outside, and the motor case (31) does not reach high temperature. Therefore, as a matter of course, reduction in size and weight can be achieved, suppression of electromagnetic noise can be achieved, and heat-resistance strength can be enhanced. Expensive components capable of resisting high temperatures are not required, and reduction in manufacturing cost can be achieved.