To improve performance by providing a means for generating a refrigerant flow in a prescribed direction in a heat source side heat exchanger either during a heating operation or during a cooling operation, a means for generating a refrigerant flow in a prescribed direction in a user side heat exchanger and a means for heat exchanging the outlet refrigerants of the respective heat exchangers.

The direction of a refrigerant flowing through an outdoor heat exchanger 2 is constant either during a cooling operation or during a heating operation. The direction of a refrigerant flowing through an indoor heat exchanger 4 is also constant either during a cooling operation or during a heating operation. Accordingly, the refrigerant flow of the outdoor heat exchanger 2 is opposed to that of the outdoor heat exchanger 4. Thus, the result coefficient COP of a heat pump system can be improved. In this way, in a separation type air conditioner, a supercooling heat exchanger 7 is provided and the refrigerant flow of the outdoor heat exchanger 2 is opposed to that of the indoor heat exchanger 4 so that a performance can be extremely improved. Therefore, only first and second check valve bridges 5 and 6 may be added.