To avoid exhaustion of heat storage during the time requiring use of cold heat and prevent remaining ice upon completion of the time requiring use of cold heat in an ice heat storage apparatus where slurry like ice is made by releasing a supercooled state of a supercooled water by previously making fitted to the condition of the use of cold heat upon ice making operation.

An apparatus is adapted such that there are provided a refrigerant circulation circuit and a water circulation circuit B, and that water is cooled in a heat storage heat exchanger 42 into a supercooled state, and the supercooled state is released with ice nuclei produced in an ice nucleus producer 46 to make ice which is in turn stored in a heat storage tank T. In the apparatus, there is provided an ice measuring unit 20 for recognizing the size of ice in a water pipe 45c utilizing a laser light scattering method upstream the heat storage tank T. capacity of the ice heat storage heat exchanger 42 is adjusted such that the size of ice recognized by the ice measuring unit 20 is suitable for the condition of the use of cold heat upon cold storage heat use operation.