A refrigeration apparatus comprising: a refrigerant circuit in which a compressor configured to compress refrigerant, a condenser configured to cause the refrigerant discharged from the compressor to reject heat and cool, an economizer configured to subcool the refrigerant having flowed out of the condenser, an expansion device configured to reduce pressure of and expand the refrigerant subcooled in the economizer, and an evaporator configured to cause the refrigerant reduced in pressure and expanded in the expansion device to receive heat and evaporate, are connected by a refrigerant pipe; an inverter device configured to drive the compressor; an inverter heat radiating unit configured to reject heat generated in the inverter device; an inverter cooling circuit including a subcooling circuit in which a refrigerant flow passage is formed that branches off from between the economizer and the expansion device, extends through the economizer and the inverter heat radiating unit, and then extends into the compressor; a flow rate regulation device provided in the inverter cooling circuit and configured to regulate a flow rate of refrigerant that is to flow into the inverter heat radiating unit; an inverter temperature detection device configured to detect a temperature of the inverter heat radiating unit as a heat radiating unit temperature; a state detection unit configured to detect a state of refrigerant flowing through the economizer; and a controller configured to, based on the heat radiating unit temperature detected in the inverter temperature detection device and the state of refrigerant flowing through the economizer detected by the state detection unit, control action of the flow rate regulation device, wherein the controller includes a temperature determination unit configured to determine whether the heat radiating unit temperature is within a target temperature range, a superheat degree calculation unit configured to calculate a degree of superheat of refrigerant flowing through the economizer from the state of refrigerant detected in the state detection unit, and an opening degree control unit configured to, when the temperature determination unit determines that the heat radiating unit temperature is within the target temperature range, control an opening degree of the flow rate regulation device so that the degree of superheat calculated in the superheat degree calculation unit reaches a target degree of superheat, and configured to, when the temperature determination unit determines that the heat radiating unit temperature is outside the target temperature range, control the opening degree of the flow rate regulation device so that the heat radiating unit temperature falls within the target temperature range. a refrigerant circuit in which a compressor configured to compress refrigerant, a condenser configured to cause the refrigerant discharged from the compressor to reject heat and cool, an economizer configured to subcool the refrigerant having flowed out of the condenser, an expansion device configured to reduce pressure of and expand the refrigerant subcooled in the economizer, and an evaporator configured to cause the refrigerant reduced in pressure and expanded in the expansion device to receive heat and evaporate, are connected by a refrigerant pipe; an inverter device configured to drive the compressor; an inverter heat radiating unit configured to reject heat generated in the inverter device; an inverter cooling circuit including a subcooling circuit in which a refrigerant flow passage is formed that branches off from between the economizer and the expansion device, extends through the economizer and the inverter heat radiating unit, and then extends into the compressor; a flow rate regulation device provided in the inverter cooling circuit and configured to regulate a flow rate of refrigerant that is to flow into the inverter heat radiating unit; an inverter temperature detection device configured to detect a temperature of the inverter heat radiating unit as a heat radiating unit temperature; a state detection unit configured to detect a state of refrigerant flowing through the economizer; and a controller configured to, based on the heat radiating unit temperature detected in the inverter temperature detection device and the state of refrigerant flowing through the economizer detected by the state detection unit, control action of the flow rate regulation device, wherein the controller includes a temperature determination unit configured to determine whether the heat radiating unit temperature is within a target temperature range, a superheat degree calculation unit configured to calculate a degree of superheat of refrigerant flowing through the economizer from the state of refrigerant detected in the state detection unit, and an opening degree control unit configured to, when the temperature determination unit determines that the heat radiating unit temperature is within the target temperature range, control an opening degree of the flow rate regulation device so that the degree of superheat calculated in the superheat degree calculation unit reaches a target degree of superheat, and configured to, when the temperature determination unit determines that the heat radiating unit temperature is outside the target temperature range, control the opening degree of the flow rate regulation device so that the heat radiating unit temperature falls within the target temperature range.