To provide a waste gas processing combustor of which the decomposition rate of waste gas is high, and the maintenance interval for cleaning is prolonged.

An annular flame stabilizing part 15 facing a combustion chamber 11, closed with a bottom plate 14, and sandwiched between an inner wall 12 and an outer wall 13 is provided. A combustion assisting gas flame hole 23 is formed in one of the inner wall 12 and the outer wall 13 so that the combustion assisting gas B may be jetted toward the flame stabilizing part 15 to form a swirl, and a waste gas flame hole 22 is formed in the other of the inner wall 112 and the outer wall 13 so that waste gas A may be jetted toward the flame insulating part 15 to form a swirl in the same rotational direction as the combustion assisting gas B, both being opposed to each other.