An ejector draws a refrigerant on a downstream side of an exterior heat exchanger serving as an evaporator, from a refrigerant suction port by a suction effect of an injection refrigerant injected from a nozzle portion for decompressing a part of the refrigerant discharged from a compressor, and mixes the injection refrigerant with the suction refrigerant to pressurize the mixed refrigerant at a diffuser. The refrigerant flowing out of the diffuser is drawn into the compressor. In this way, the density of the refrigerant drawn into the compressor can be increased, thereby suppressing reduction in flow amount of the refrigerant flowing into an interior condenser serving as a radiator. Thus, even if the temperature of the outside air (heat-absorption target fluid) is decreased, the interior condenser is prevented from degrading its heating capacity for the ventilation air (heating target fluid).