In a refrigerant circuit (5) of an air conditioner (1), a single-stage compression refrigeration cycle is performed. In the refrigerant circuit (5), a second heat exchanger (40) is provided downstream a first heat exchanger (30). In the first heat exchanger (30), high-pressure refrigerant of a high-pressure flow path (31) is cooled by exchanging heat with first intermediate-pressure refrigerant of an intermediate-pressure flow path (32). First intermediate-pressure gas refrigerant generated in the first heat exchanger (30) is supplied to a first compression mechanism (71). Second intermediate-pressure refrigerant having a pressure lower than that of the first intermediate-pressure refrigerant is supplied to an intermediate-pressure flow path (42) of the second heat exchanger (40). In the second heat exchanger (40), high-pressure refrigerant of a high-pressure flow path (41) is further cooled by exchanging heat with the second intermediate-pressure refrigerant of the intermediate-pressure flow path (42). Second intermediate-pressure gas refrigerant generated in the second heat exchanger (40) is supplied to a second compression mechanism (72).