To reduce the number of components by integrating a part of a reduction gear transmission mechanism with a second case, to realize fixing of a drive source or a shaft of a gear, to facilitate securing of a distance between centers of gears and computing of a strength, and to raise a strength.

The geared motor 14 includes the drive source 14, the reduction gear transmission mechanism 40 coupled to this drive source 14 for decelerating the rotary output of the drive source 14 to transmit the rotary output to an output unit 28, a first case 32 for fixing the drive source 14, a second case 33 cooperated with the first case 32 to form a space for containing the drive source 14 and to form the reduction gear transmission mechanism 40, and a third case 34 for covering the reduction gear transmission mechanism 40. A part of the reduction gear transmission mechanism 40 is integrated with the second case 33 and formed.