PROBLEM TO BE SOLVED: To provide a technique capable of appropriately meeting a demand to operate a hot water supply system so as to save fuel and power expenses and a demand to operate the hot water supply system while saving energy.SOLUTION: A hot water supply system disclosed in the present specification comprises: a heat pump heating water; and a tank storing water. The hot water supply system can execute a boiling-up operation for boiling up the water in the tank by the heat pump in either a midnight boiling-up mode or a learning boiling-up mode. In the midnight boiling-up mode, the hot water supply system executes the boiling up operation so as to store necessary calorie in the tank in a midnight time zone to which midnight power charges are applied. In the learning boiling-up mode, the hot water supply system executes the boiling-up operation so as to store necessary calorie in the tank by predicted hot water supply start time on the basis of previous hot water supply records.
