To improve the safety and comfort in a cabin during the traveling by setting a first in-cabin heat exchanger in the low temperature and low pressure condition, and setting a second in-cabin heat exchanger in the high temperature and high pressure condition even when a vehicle is operated in any condition.

The refrigerant of high temperature and high pressure discharged from a compressor 1 enters a four-way control valve 7 through a second in-cabin air heat exchanger 11 during the cooling operation. The refrigerant is switched to an out-of-cabin heat exchanger 2, and after the refrigerant is condensed and liquefied through the heat exchange by the out-of-cabin air heat exchanger 2, decompression is achieved by a refrigerant throttling device 4. The refrigerant is introduced into a first in-cabin air heat exchanger 10 through the four-way control valve 7 and a three-way control valve 14, and evaporated through the heat exchange, and returned to the compressor 1. The first in-cabin air heat exchanger 10 is in the low temperature and low pressure condition. Also in the heating operation, the four-way control valve 7 and the three-way control valve 14 are switched so that the first in-cabin air heat exchanger 10 is in the low temperature and low pressure condition.