In a heat-accumulation operation mode, fluid which flows out of a first heat exchanger 22 heats hot water in a heat accumulator tank 55. In a cooling operation mode, a third heat exchanger 53 absorbs heat. When the heat-accumulation operation mode is changed to the cooling operation mode, a cold/hot water supply apparatus determines whether fluid which flows out of the first heat exchanger 22 should be made to flow to the third heat exchanger 53 or the first heat exchanger 22 based on temperature of fluid detected by a temperature sensor 70 disposed on the first heat exchanger 22. It is possible to suppress deterioration of comfort in an indoor space in the cooling operation mode.