A catalytic combustion apparatus with good exhaust gas characteristics, which effectively uses radiation from a catalyst body and which enhances the heat exchanger efficiency. The apparatus comprises a plate-shaped catalyst body (7) having communication holes for combustion of a mixture of fuel gas and air, and a combustion chamber (6) which receives therein the catalyst body (7) and of which a part of side walls is defined by a radiation heat receiving plate (11) facing either of both surfaces of the catalyst body (7).
