A refrigeration cycle apparatus comprising: a compressor configured to compress refrigerant; a flow path switching device connected to the compressor; a first heat exchanger connected to the flow path switching device and having a first heat exchange unit and a second heat exchange unit; a flow path changing device connecting the first heat exchange unit and the second heat exchange unit to each other; a first expansion valve connected to the first heat exchange unit and the second heat exchange unit; and a second heat exchanger connected to the first expansion valve and the flow path switching device, the flow path switching device being configured to switch flow of the refrigerant compressed by the compressor between flow to the first heat exchanger and flow to the second heat exchanger, the flow path changing device being configured to switch flow of the refrigerant among flow successively through the first heat exchange unit and the second heat exchange unit, flow in parallel through the first heat exchange unit and the second heat exchange unit, and flow through any one of the first heat exchange unit and the second heat exchange unit, characterised in that the flow path changing device comprises a first on-off valve, a second on-off valve, a third on-of valve, a second expansion valve connected between a branch point either between the second on-off valve and the second heat exchange unit or between the second heat exchange unit and the third on-off valve and the first expansion valve, and a third expansion valve connected between the first on-off valve and the first expansion valve; wherein the flow path switching device has a first four-way valve and a second four-way valve, the first four-way valve is connected to the first heat exchange unit, the second four-way valve is connected to the second heat exchange unit and the first four-way valve, by switching between the first four-way valve and the second four-way valve, one of the first heat exchange unit and the second heat exchange unit which is not used has low pressure when the other of the first heat exchange unit and the second heat exchange unit is used; and wherein when the first heat exchange unit is used during low-outside-temperature cooling operation and low-capacity cooling operation, the first four-way valve and the second four-way valve are switched to a cooling mode, the first on-off valve is opened, the second on-off valve and the third on-off valve are closed, the second expansion valve is closed, and the third expansion valve is opened. a compressor configured to compress refrigerant; a flow path switching device connected to the compressor; a first heat exchanger connected to the flow path switching device and having a first heat exchange unit and a second heat exchange unit; a flow path changing device connecting the first heat exchange unit and the second heat exchange unit to each other; a first expansion valve connected to the first heat exchange unit and the second heat exchange unit; and a second heat exchanger connected to the first expansion valve and the flow path switching device, the flow path switching device being configured to switch flow of the refrigerant compressed by the compressor between flow to the first heat exchanger and flow to the second heat exchanger, the flow path changing device being configured to switch flow of the refrigerant among flow successively through the first heat exchange unit and the second heat exchange unit, flow in parallel through the first heat exchange unit and the second heat exchange unit, and flow through any one of the first heat exchange unit and the second heat exchange unit, characterised in that the flow path changing device comprises a first on-off valve, a second on-off valve, a third on-of valve, a second expansion valve connected between a branch point either between the second on-off valve and the second heat exchange unit or between the second heat exchange unit and the third on-off valve and the first expansion valve, and a third expansion valve connected between the first on-off valve and the first expansion valve; wherein a second expansion valve connected between a branch point either between the second on-off valve and the second heat exchange unit or between the second heat exchange unit and the third on-off valve and the first expansion valve, and a third expansion valve connected between the first on-off valve and the first expansion valve; the flow path switching device has a first four-way valve and a second four-way valve, the first four-way valve is connected to the first heat exchange unit, the second four-way valve is connected to the second heat exchange unit and the first four-way valve, by switching between the first four-way valve and the second four-way valve, one of the first heat exchange unit and the second heat exchange unit which is not used has low pressure when the other of the first heat exchange unit and the second heat exchange unit is used; and wherein when the first heat exchange unit is used during low-outside-temperature cooling operation and low-capacity cooling operation, the first four-way valve and the second four-way valve are switched to a cooling mode, the first on-off valve is opened, the second on-off valve and the third on-off valve are closed, the second expansion valve is closed, and the third expansion valve is opened.