PURPOSE: To obtain a heat storage panel device which stores heat and which releases the heat from the surface thereof or introduces water thereinto and supplies hot water therefrom, in regard to hot water supply equipment using gas, petroleum, a solar heat or a waste heat.

CONSTITUTION: A piping 4 of a hot water inlet part 2 and a hot water outlet part 3 is laid inside a box-shaped panel 1 and indentations 6 are formed on the surface of the piping 4, while a heat storage material 5 is filled up in the box-shaped panel 1. When hot water is introduced into the box-shaped panel 1 from the hot water inlet part 2, the heat thereof is stored by the heat storage material 5 filled up therein and the water is discharged from the hot water outlet part 3. On the occasion of the heat storage stated above, the indentations 6 transfer the heat effectively to the heat storage material 5. In the case when the indentations 6 are constituted of knurled parts, monolithic molding with the piping 4 is facilitated and the device can be manufactured inexpensively. In the case when the device is used for a drier, a heater or the like, for instance, it may be made to release the heat gradually from the whole of it or may be used for supplying hot water by introducing water thereinto.