To reduce the necessary quantity of an enclosed refrigerant.

A first check valve 620 is mounted in a hot gas pathway 600 for guiding a refrigerant discharged from a compressor 100 to an evaporator 300, bypathing a discharger 200 and an ejector 400. The first check valve 620 allows the refrigerant to flow from the compressor 100 only toward the evaporator 300 (a refrigerant pathway 510). Accordingly, as the refrigerant is prevented from flowing into the hot gas pathway 600 in the normal operation, the refrigerant flowing into the hot gas pathway 600 from the low pressure side is prevented from residing (sleeping) in the hot gas pathway 600 during the normal operation, so that the necessary quantity of the enclosed refrigerant can be reduced and the manufacturing cost of the ejector cycle can be reduced.