PURPOSE: To improve the arrangement of cord to facilitate its assembling and improve dimensional accuracy by making a motor holder from synthetic resin and forming a guide having a recess in said motor holder to allow the movement of motor cord.

CONSTITUTION: A motor holder 3 mounted in a housing body of synthetic resin is made from synthetic resin and an engagement recess 27 for allowing the movement of two motor cords fixed to the holder 3 is formed on a guide part 25. And there are provided two engagement protrusions 39, 40 for the arrangement of switch cord, a through hole of an output shaft of the motor, and through holes 30, 36 for supporting respectively a first and second gear shaft of a reduction gears. Since the motor cords are engaged with the recess 27 to assemble them, the cords do not disturb the assembly, thereby making the handling thereof easier, while troubles such that the cord moves and contacts an operating member can be prevented and dimensional accuracy can be improved.