To recognize the existence state of ice in a water circulation circuit in an ice heat storage apparatus for supercooling water circulating in the ice circulation circuit and releasing the supercooling to make ice.

An ice making apparatus is adapted such that there are provided a refrigerant circulation circuit and a water circulation circuit B, and that water is cooled into a supercooled state in a heat storage heat exchanger 42, and the supercooled state is refleasing with ice nuclei produced in an ice nucleus production unit 46 for making ice. In the apparatus, there is provided an ice measuring unit 20 which recognizes the number of ice blocks and the size of each ice block in a water pipe 45c utilizing a laser scattering method of laser light upstream the heat storage treat exchanger 42. Utilizing the number of ice blokes and the size of each ice block recognized by the ice measuring unit 20 there is estimated capacity of each instrument upon inspection of an apparatus, and there is predicted freezing of the heat storage heat exchanger 42 upon ice making operation.