PURPOSE: To obtain a carbonization furnace, excellent in efficiency and throughput and useful for carrying out the carbonization treatment of waste materials, etc., by arranging an inner furnace in an outer furnace with a gap placed therebetween and using the gap as a combustion chamber.

CONSTITUTION: The objective carbonization furnace is obtained by arranging an inner furnace 1 which is a dry distillation furnace in an outer furnace 3 with a gap 9 placed therebetween, using the gap 9 as a combustion chamber 9, preferably forming the outer and inner furnace 3 and 1 into a transverse long shape and further providing an opening and closing part for carrying in and out a material in the longitudinal direction thereof.