PURPOSE: To decompose waste in various forms for disposal in a manner wherein no smoke or harmful gas is produced and no malodor or noise is emitted when it is being burned.

CONSTITUTION: A crucible 16 having a space for receiving the waste to be burned is provided and supported within a furnace 7 in a manner wherein a space 17 is defined between the entire outer periphery of the crucible 16 and the wall of the furnace 7 except at the crucible supporting part and wherein the opening part of the crucible 16 is located inwardly of the opening part of the furnace 7, an opening and closing lid 15 is provided to close these opening parts simultaneously and a suction pipe 26 is provided to carry out of the crucible 16 the gas produced therein when the waste is being burned with the crucible 16 kept vacuous by closing the aforesaid lid 15. A heating device is provided to heat the crucible 16 in the space 17, an exhaust pipe 24 is provided communicating with the space 17 and extending from the furnace 7 and the crucible 16 is made of the material capable of producing far infrared rays and high in heat conductivity.