An ice making system comprising: a refrigerant circuit that is configured for performing a vapor compression refrigeration cycle, the refrigerant circuit including a compressor, a condenser that is configured such that it, during operation of the ice making system, condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that is configured such that it, during operation of the ice making system, decompresses the refrigerant from the condenser, a flooded evaporator that is configured such that it, during operation of the ice making system, evaporates the refrigerant decompressed by the first expansion valve, and a superheater that is configured such that it, during operation of the ice making system, imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that is configured such that it, during operation of the ice making system, circulates a medium to be cooled, which is cooled by the flooded evaporator; and a subcooling device that is configured such that it, during operation of the ice making system, subcools the refrigerant that has flowed out of the condenser, wherein the ice making system further comprises a control device which is configured to control the opening degree of the first expansion valve such that the superheater imparts, to the refrigerant discharged from a refrigerant outlet of the flooded evaporator, a degree of superheating to coincide with a predetermined target value so that dryness (x) of the refrigerant discharged from the refrigerant outlet of the flooded evaporator is kept within a predetermined range of less than 1, and wherein the superheater is configured such that it, during operation of the ice making system, superheats the refrigerant discharged from the flooded evaporator using the refrigerant subcooled by the subcooling device, and the control device is further configured to control a capacity of the subcooling device such that a temperature of the refrigerant subcooled by the subcooling device is maintained constant. a refrigerant circuit that is configured for performing a vapor compression refrigeration cycle, the refrigerant circuit including a compressor, a condenser that is configured such that it, during operation of the ice making system, condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that is configured such that it, during operation of the ice making system, decompresses the refrigerant from the condenser, a flooded evaporator that is configured such that it, during operation of the ice making system, evaporates the refrigerant decompressed by the first expansion valve, and a superheater that is configured such that it, during operation of the ice making system, imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that is configured such that it, during operation of the ice making system, circulates a medium to be cooled, which is cooled by the flooded evaporator; and a subcooling device that is configured such that it, during operation of the ice making system, subcools the refrigerant that has flowed out of the condenser, wherein the ice making system further comprises a control device which is configured to control the opening degree of the first expansion valve such that the superheater imparts, to the refrigerant discharged from a refrigerant outlet of the flooded evaporator, a degree of superheating to coincide with a predetermined target value so that dryness (x) of the refrigerant discharged from the refrigerant outlet of the flooded evaporator is kept within a predetermined range of less than 1, and wherein the superheater is configured such that it, during operation of the ice making system, superheats the refrigerant discharged from the flooded evaporator using the refrigerant subcooled by the subcooling device, and the control device is further configured to control a capacity of the subcooling device such that a temperature of the refrigerant subcooled by the subcooling device is maintained constant.