To provide a storage type hot water supply system which has enhanced total primary energy of a heat pump and an auxiliary heat source machine during the hot water supply operation.

A storage type hot water supply system includes a maximum primary energy efficiency temperature determination part 123 that assumes a hot water supply operation in which water at a water supply temperature Tw in a hot water storage tank 11 is heated to a temperature equal to or lower than a target hot water supply temperature by a heat pump 51 under an outside air temperature Tout, then, hot water to be supplied from the hot water storage tank 11 to a hot water supply pipe 13 is heated to a set temperature Tcm by a water heater 87, and supplied to a hot water supply pipe 86. The maximum primary energy efficiency temperature determination part 123 then determines the maximum primary energy efficiency temperature Tre_max being a boiling temperature at which the total primary energy efficiency of the heat pump 51 and the water heater 87 in the assumed hot water supply operation becomes the maximum.