To reduce the cost of parts and man-hour for assembly by integrally composing a driving unit of a fan motor unit, hot air housing and heater unit and mounting the driving unit through a vibration proof mechanism onto the case main body.

Before a fan motor 30 is mounted inside a case main body 10, a driving unit 20a is integrally composed of the fan motor 30, hot air housing 20 and heater unit. Then, the positions of bearing surface flanges 91a, 92a and 93a of a fixed plate 91 are mutually matched so as to face bearing surface parts 31a, 32a and 33a of a connection bracket 31, etc. At this time, a vibration proof mechanism 80 is interposed at a gap between the bearing surface flanges and the bearing surface parts. Since the driving unit 20a is mounted through the respective vibration proof mechanisms 80 onto the case main body 10, the number of parts such as other elastic members is decreased, and man-hour for assembly is reduced as well as cost can be reduced.