PURPOSE: To supply a low cost, and simple refrigerating cycle by using an air separator on the outlet side of a condenser of a refrigerating cycle and controlling refrigerant with a single solenoid valve.

CONSTITUTION: During ordinary operation, a first solenoid valve 5 is opened. The refrigerant discharged from a compressor 1 is introduced to a pressure reducing device 10 by way of a condenser 2, and separated into liquid phase and air phase. The separated refrigerant is introduced to an air separator 9 by way of a refrigerant pipe 12. The refrigerant is separated into a vapor drain side 11 and a liquid drain side 13 in the air separator 9. There are two circuits available, One is the circuit where the cooling medium flows from the vapor drain side 11 to a pressure reducing device 7 while the other is the circuit where it flows from the liquid drain side 13 to the first solenoid valve 5. Almost every refrigerant flows to the first solenoid valve 5 where there is available the liquid refrigerant having larger specific volume. During low temperature operation, the first solenoid valve is closed. The refrigerant introduced to the air separator 9 is adapted to flow only to a refrigerant pipe 11' installed to the vapor drain side 11.