To achieve a smokeless and colorless treatment of unburned gas generated during the cremation disposal to accomplish accurate combustion thereof in a re-combustion chamber.

In this re-combustion apparatus for a cremation furnace, an unburned gas generated in a main combustion chamber 1 is fluidized to a re- combustion chamber 3 through a flue 2 and re-burned to be released. A gas release port part 4 of the re-combustion chamber 3 is provided with an oxygen sensor 16 and the re-combustion chamber 3 is provided with an air nozzle 12 to inject an indicated amount of air obtained by measuring the sufficiency or insufficiency of oxygen with respect to a detection signal of the oxygen sensor 16.