A refrigeration apparatus comprising: a high-temperature-side circulation circuit in which a high-temperature-side compressor, a high-temperature-side condenser, a high-temperature-side expansion valve, and a high-temperature-side evaporator are connected in series; a low-temperature-side circulation circuit in which a low-temperature-side compressor, a low-temperature-side condenser, an HIC (Heat Inter Changer) heat exchanger, a low-temperature-side expansion valve, and a low-temperature-side evaporator are connected in series; a cascade condenser that connects the high-temperature-side evaporator and the low-temperature-side condenser in a heat exchangeable manner; an injection circuit that branches off between the HIC heat exchanger and the low-temperature-side expansion valve, and is connected to an inside of the low-temperature-side compressor; characterised in that a refrigerant mixture including C02 and R32 and having a ratio of R32 to a whole refrigerant mixture of 50 to 74% flows through the low-temperature-side circulation circuit; a flow control valve is provided in the injection circuit and is configured to adjust a pressure of refrigerant flowing into the injection circuit; a low-temperature-side discharge thermometer is configured to measure a temperature of gas discharged from the low-temperature-side compressor; an electromagnetic injection valve is provided in the injection circuit and is configured to adjust an amount of refrigerant flowing into the low-temperature-side compressor; and a controller is configured to give an instruction to the electromagnetic injection valve in accordance with a measured value of the low-temperature-side discharge thermometer, wherein heat exchange is performed between the injection circuit and the HIC heat exchanger, and wherein the controller is configured to raise an opening degree of the electromagnetic injection valve when the measured value of the low-temperature-side discharge thermometer exceeds a predetermined value, and is configured to reduce the opening degree of the electromagnetic injection valve when the measured value of the low-temperature-side discharge thermometer falls below the predetermined value. a high-temperature-side circulation circuit in which a high-temperature-side compressor, a high-temperature-side condenser, a high-temperature-side expansion valve, and a high-temperature-side evaporator are connected in series; a low-temperature-side circulation circuit in which a low-temperature-side compressor, a low-temperature-side condenser, an HIC (Heat Inter Changer) heat exchanger, a low-temperature-side expansion valve, and a low-temperature-side evaporator are connected in series; a cascade condenser that connects the high-temperature-side evaporator and the low-temperature-side condenser in a heat exchangeable manner; an injection circuit that branches off between the HIC heat exchanger and the low-temperature-side expansion valve, and is connected to an inside of the low-temperature-side compressor; characterised in that a refrigerant mixture including C02 and R32 and having a ratio of R32 to a whole refrigerant mixture of 50 to 74% flows through the low-temperature-side circulation circuit; a flow control valve is provided in the injection circuit and is configured to adjust a pressure of refrigerant flowing into the injection circuit; a low-temperature-side discharge thermometer is configured to measure a temperature of gas discharged from the low-temperature-side compressor; an electromagnetic injection valve is provided in the injection circuit and is configured to adjust an amount of refrigerant flowing into the low-temperature-side compressor; and a controller is configured to give an instruction to the electromagnetic injection valve in accordance with a measured value of the low-temperature-side discharge thermometer, wherein heat exchange is performed between the injection circuit and the HIC heat exchanger, and wherein the controller is configured to raise an opening degree of the electromagnetic injection valve when the measured value of the low-temperature-side discharge thermometer exceeds a predetermined value, and is configured to reduce the opening degree of the electromagnetic injection valve when the measured value of the low-temperature-side discharge thermometer falls below the predetermined value.