Ejector cycle system

In an ejector cycle system, high-pressure side refrigerant is decompressed by an ejector (400) in cooling operation for cooling a compartment, and is decompressed by a fixed restrictor (640) in heating operation for heating the compartment. Therefore, in the heating operation, the pressure of refrigerant to be sucked into a compressor (100) can be made lower, and the temperature of refrigerant discharged from the compressor is increased. Alternatively, in the cooling operation, a flow direction of refrigerant flowing through at least one of an exterior heat exchanger (200) and an interior heat exchanger (300) is identical to that in the heating operation.