To smoothly burn municipal refuse and industrial waste, etc., avoiding thermal damage of a fire grate by directly measuring temperature in a refuse layer, controlling an opening of an air supply damper comparing the measured temperature and set temperature, and supplying a proper combustion air amount.

A water cooling temperature detection pipe 1 amplifies and detects electromotive force from a K-type sheath thermocouple 13 protruded on the tip end thereof with a measurement unit 14, and introduces a temperature signal to a personal computer 16 through a signal cable 15. When temperature data incorporated into the personal computer 16 from the measurement unit 14 through the signal cable 15 becomes an upper limit value or more or a lower limit value or lower, an adjusting signal from a damper driving control circuit is automatically applied to an automatic damper 19 through the signal cable 17 whereby an opening of a box shaped automatic damper 19 incorporating combustion air supplied from an air fan 18 is controlled, and hence an air amount of an air box 20 is properly supplied and an optimum air amount suitable for combustion is supplied.