To provide a hot water supply device in which a heat exchange amount is not reduced with the passage of time during heat storage, and therefore, is capable of efficiently storing heat of a heat source unit.

Fluidity of a latent heat accumulating material used in the heat accumulation unit is constantly maintained even during a heat radiating operation to make it a latent heat accumulating material enabling temperature stratification. Upon accumulating heat in the heat accumulation unit, the latent heat accumulating material is made to circulate between the heat source unit and the heat accumulation unit, and at this time, the latent heat accumulating material on a low-temperature side of the latent heat accumulating material in a temperature-stratified state in the heat accumulation unit is supplied to the heat source unit. On the other hand, upon radiating heat in the heat accumulating unit, the latent heat accumulating material is made to circulate between the heat accumulation unit and a hot water supply unit, and at this time, the latent heat accumulating material on a high-temperature side of the latent heat accumulating material in a temperature-stratified state in the heat accumulation unit is supplied to the hot water supply unit.

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