To make it possible to perform long hours of power generation with low noise even in a place where there is no commercial power source by providing a thermoelectric element connected to a side surface of a diffusion plate, cooling means connected to another side surface, and power storing means connected to the circuit of the thermoelectric element and having power supply terminals connectable to the outside.

When a catalyst 6 mounted to the inner wall of a cabinet body 7 constituting a combustion chamber 5 is heated to the activation temperature, a heat generating reaction is started and a heating base 9 is heated. The heat decreases while it passes through a heat diffusion plate 10 and one of the thermoelectric element 11 is heated. Since the cooling surface of other thermoelectric element 11 is cooled by cooling means, a temperature difference is created between both the surfaces of the thermoelectric element 11 and an electromotive is created. A plurality of thermoelectric elements are connected to capacitors or secondary batteries with electric circuits, they are electrically charged. Thus, noise can be suppressed and power can be stably supplied for many hours continuously.