To provide a compact hot water supplier the height of whose body can be made small by utilizing the inner space effectively.

This is a hot water supplier which is equipped with a heat exchanger 2, a burner 3 for combustion, a blower 4 for combustion, and a controller unit 8, and which has accommodated the burner 3 under the heat exchanger 2, a blower 4 for combustion by the side of the heat exchanger 2, a controller unit 8 arranged horizontally a certain space apart under the burner 3, and a fuel supplier 7 by the side of the controller unit 8 within the body case, so the space under the burner can be utilized effectively, and the height of the hot water supplier can be made very small. Moreover, since the controller and the protective material are unitized, the insertion into the body case of the hot water supplier or the takeout becomes easy.