A hot-water supply apparatus capable of restraining the occurrence of noises from a building wall surface side includes a hot-water supply apparatus main body having a burner and a heat exchanger that generates hot water by combustion exhaust of the burner, and a rectangular parallelepiped main body case that houses the hot-water supply apparatus main body. A back plate (5c), which closes the back side of the main body case, is installed to a building wall surface (W) such that the back plate (5c) opposes the building wall surface (W) with a predetermined void space (S) provided therebetween. A soundproof member (18), which closes at least a part of an open end of the void space (S), is provided on the main body case (5).