A refrigeration cycle apparatus comprising: a main refrigerant circuit in which a compressor that compresses a refrigerant, a radiator that rejects heat of the refrigerant compressed by the compressor, a primary passage of an internal heat exchanger that exchanges heat between the refrigerant which has passed through the radiator and the refrigerant which has passed through the radiator and is to be injected into the compressor, a first pressure reducing device that reduces a pressure of the refrigerant which has passed through the primary passage of the internal heat exchanger, and an evaporator where the refrigerant that has been subjected to pressure reduction by the first pressure reducing device evaporates are sequentially connected to one another by pipes; an injection circuit in which a second pressure reducing device that reduces a pressure of the refrigerant which has passed through the radiator and is to be injected into the compressor, a secondary passage of the internal heat exchanger, and an injection port of the compressor are sequentially connected to one another by pipes; and a controller that controls an opening degree of the second pressure reducing device and a heat transfer area of the radiator, wherein, during operation of the refrigeration cycle apparatus, the high-pressure-side pressure of the refrigerant flowing through the main refrigerant circuit enters a supercritical state, and wherein the radiator is divided into a plurality of units (2a, 2b) so as to form parallel flows of the refrigerant in the radiator, and the controller adjusts the opening degree of the second pressure reducing device and blocks passage of the refrigerant through one or some of the divided units (2a, 2b) to reduce the heat transfer area of the radiator, so as to increase a high-pressure-side pressure if the operation state is under an overload condition in which both outside and inside air temperatures are high. a main refrigerant circuit in which a compressor that compresses a refrigerant, a radiator that rejects heat of the refrigerant compressed by the compressor, a primary passage of an internal heat exchanger that exchanges heat between the refrigerant which has passed through the radiator and the refrigerant which has passed through the radiator and is to be injected into the compressor, a first pressure reducing device that reduces a pressure of the refrigerant which has passed through the primary passage of the internal heat exchanger, and an evaporator where the refrigerant that has been subjected to pressure reduction by the first pressure reducing device evaporates are sequentially connected to one another by pipes; an injection circuit in which a second pressure reducing device that reduces a pressure of the refrigerant which has passed through the radiator and is to be injected into the compressor, a secondary passage of the internal heat exchanger, and an injection port of the compressor are sequentially connected to one another by pipes; and a controller that controls an opening degree of the second pressure reducing device and a heat transfer area of the radiator, wherein, during operation of the refrigeration cycle apparatus, the high-pressure-side pressure of the refrigerant flowing through the main refrigerant circuit enters a supercritical state, and wherein the radiator is divided into a plurality of units (2a, 2b) so as to form parallel flows of the refrigerant in the radiator, and the controller adjusts the opening degree of the second pressure reducing device and blocks passage of the refrigerant through one or some of the divided units (2a, 2b) to reduce the heat transfer area of the radiator, so as to increase a high-pressure-side pressure if the operation state is under an overload condition in which both outside and inside air temperatures are high.