An internal heat exchanger and a first flow control valve are connected in series between a condenser and a refrigerant inlet of an ejector. A gas refrigerant outlet of a gas-liquid separator is connected to a suction port of a compressor. A first bypass circuit connects a refrigerant outlet of the condenser to an intermediate pressure portion of the compressor via a second flow control valve and the internal heat exchanger. A second bypass circuit connects a refrigerant outlet of the internal heat exchanger to the liquid refrigerant outlet of the gas-liquid separator via a third flow control valve. While the second flow control valve is opened such that the refrigerant flows through the first bypass circuit, the fourth flow control valve is switched to be opened or closed, and the third flow control valve is switched to be closed or opened.