To solve the problem that in a production line, when a motor is supported by vibration-proofing to a body by a retaining member through a vibration-proofing material, the engaging sizes of them are tight, the vibration-proofing material is largely deformed, it is hard to mount the motor at predetermined position and angle, and a production efficiency is bad.

A projection 11b is provided at the bottom of a recess 11a which engages the vibration-proofing material 12 of a motor supporting section 11 provided at the center section of a casing 6 for constituting a body, and a recess 12b is provided at the position corresponding to the projection 11b of the vibration-proofing material 12. The motor 13 is sandwiched between the vibration-proofing materials 12 and 14. The vibration-proofing material 12 is engaged with the recess 11a of the motor supporting section 11, and the vibration-proofing material 14 is engaged with the recess 15a of the retaining member 15. Then, when the retaining member 15 is clamped at the casing 6, the motor 13 is converged at the predetermined position and angle.