A heat pump cycle includes a compressor, a first interior heat exchanger, a separator that separates a refrigerant discharged from the compressor into a gas-phase refrigerant which does not include a lubricant and a remaining refrigerant, an exterior heat exchanger that performs heat exchange between the remaining refrigerant flowing out of the separator and an outside air, a second interior heat exchanger, a control valve, an accumulator, and a first bypass passage that bypasses the second interior heat exchanger and connects to an inlet side of the accumulator. The heat pump cycle heats an air flow in the first interior heat exchanger and controls the control valve to reduce the pressure of the refrigerant, in a state where the refrigerant circulates in a refrigerant circuit including the first bypass passage while accumulating the gas-phase refrigerant flowing out of the separator in the second interior heat exchanger.