PURPOSE: To cool an inverter efficiently by providing an air passage connected to a blow-off air passage and to blow a part of the cooling air to an inverter chamber.

CONSTITUTION: At the inside of the room 13, a blow-off air passage to blow off a cool air heat-exchanged by heat exchangers 19a and 19b at the indoor side into the room in a cooling operation is provided. And an inverter chamber 16 to house an inverter 15 is also provided. In this case, a communicating duct 20 connected to the blow-off air passage and to pass a part of the cooling air to the inverter chamber 16 is provided. As a result, a part of the cooling air heat-exchanged by the heat exchangers 19a and 19b at the indoor side is passed to the inverter chamber 16 to cool the inverter 15 forcibly, and thereby, the inverter 15 can be cooled efficiently.