PURPOSE: To enable the use of a smoke coal material of a wide range, to provide excellent heat utilizing ability, and to enable sharp reduction of the generation of a noxious component in exhaust gas by a method wherein a chimney, a combustion chamber, a reburner, and a conical umbrella part located at a lower end part are located in a cylindrical container.

CONSTITUTION: A chimney 2 is mounted in a manner to extend through the central part of the top wall of a container 1, the central part, protruded in the container 1, of the chimney is expanded to form a reburner 6. A umbrella part 9 and a cylindrical outer peripheral wall 10 spread toward above are located in a combustion chamber 8 situated below the chimney 2. In this constitution, when a shutter 13 is opened and smoked coal is dropped from the combustion chamber 8, the conical shape of the outer peripheral wall 10 increases efficiency. Further, by taking out smoked coal, a material is naturally dropped and enters the combustion chamber 8. Combustion is continued, an amount of a material is limited to a proper value by means of the umbrella part 9, combustion performance is further improved to further improve quality of smoked coal. In the reburner chamber 6, incomplete combustion gas, e.g. carbon monoxide, and a tar content in flue gas are ignited for recombustion, a flue gas temperature is increased and the generation of a noxious gas component, simultaneously, is sharply reduced.