To provide an ice storage system for cooling equipment which levels electric energy without the necessity of providing a specific facility, such as a brine circuit.

The system is provided with a refrigerant circuit 6, a heat storage water tank 14 having a refrigeration side heat exchanger 15, a solenoid valve 21 for supercooling, and an electromagnetic valve 22 for ice making. The circuit 6 has a constitution in which a compressor 8, a condenser 9, an expansion valve 10, a cooler 11 for cooling a refrigeration show case 2, and the like, are annularly connected. The system is also provided with a channel control means which determines whether to allow the solenoid valve 22 to take an ice making process in which ice is made in the tank 14 by flowing the refrigerant that has passed through the compressor 9 and depressurized thereafter, to the heat exchanger 15, or to allow the solenoid valve 21 to take a supercooling process of the refrigerant by flowing the refrigerant that has passed through the compressor 9 to the heat exchanger 15 without depressurization and then to the expansion valve 10.