PURPOSE: To provide an ice heat storage device, utilizing an ice making efficiency due to supercooling, which is higher compared with direct contact heat exchange, capable of making ice continuously without bothering the ice making due to the adhesion and growth of ice on a releasing plate and stabilized.

CONSTITUTION: An ice heat storage device is provided with a heat storage tank 1, a supercooler 4, cooling water to a supercooled condition, a communicating unit 1a, connecting the supercooler 4 to the heat storage tank 1, a circulating line for supplying water in the heat storage tank 1 into the supercooler 14, second liquid 8, having a solidifying point, lower than water, effecting heat exchange in the supercooler 4, never being mixed and combined with each other and insoluble, an injecting means 6, injecting the second liquid 8 into the half way of the communicating unit, a pump 2, circulating the second liquid 8 from a reserving unit to the supercooler 4, and a refrigerating means 3 whereby continuous ice making becomes possible.