PURPOSE: To integrate a ventilator and an air-conditioner by providing a ventilation chamber containing a full-heat exchanger in adjacent to the outdoor machine room of air-conditioner.

CONSTITUTION: Outer air is fed through a suction fan 15 to a full-heat exchanger while room air is fed through an exhaust fan 14 to said exchanger 3. Through heat-exchange between the outer air 4 and contaminated room air 5, heat recovered outer air 6 is produced and fed through a suction fan 15 and an air flow path 19 in the outdoor machine chamber 17 to the return port 20 of air-conditioner 20 in the indoor machine room 16, where it is mixed with the return air 21 circulated from the cabin 22 and fed to an indoor heat-exchanger 11. The mixed air of said air-conditioned outer air 6 and cabin return air 21 is fed through a chassis side distribution duct 23 into the cabin. Consequently, a ventilator containing a full-heat exchanger and an air-conditioner can be integrated resulting in reduction of man power required to install on the roof of car.