To provide a storage type hot water supply system whose running cost during the hot water supply operation can be reduced.

A storage type hot water supply system includes a minimum running cost temperature determination part 122 that assumes a hot water supply operation in which water at a water supply temperature in a hot water storage tank 11 is heated to a predetermined boiling temperature by a heat pump 51 at an ambient outside air temperature, and then, hot water at a boiling temperature to be supplied to a hot water supply pipe 13 from the hot water storage tank 11 is heated to a set temperature by a water heater 87, and supplied to the hot water supply pipe 13. The minimum running cost temperature determination part 122 then determines the minimum running cost temperature being a boiling temperature at which the total cost of the running cost of the heat pump 51 and the running cost of the water heater 87 in the assumed hot water supply operation becomes the minimum.