PURPOSE: To provide the title incinerator in which unstable burning is not caused, by a method wherein a fluidized bed is divided into a plurality of divisions and supplied gas can be independently controlled at each of the division.

CONSTITUTION: At the inside of a space 4, in which waste is pyrolyzed as the major function, two shield plates 10, 11 are provided and the space is divided into three divisions, i.e., a drying division 12, a pyrolyzing and gasifying division 13 and a carbides-burning division 14. At the bottom of an incinerator 1, diffusers 15, 16, 17, each of which consists of a diffusing plate and a wind box, are individually fixed corresponding to these three divisions. Inert gas such as exhaust gas is supplied into an inert gas-supplying pipe 19 by a blower 18 and it is joined respectively to the diffusers 15, 16, 17 through flow control valves 20, 22, 24 and pipes 21, 23, 25. On the other hand, the primary air is supplied into an air-supplying pipe 28, and it is joined respectively to the diffusers 16, 17 through flow control valves 29, 31 and pipes 30, 32. Pyrolyzing- gasifying and burning each are independently done at the divisions for these purposes, by controlling these flow control valves.