To provide a carbonization oven that facilitates the inspection and cleaning.

The objective carbonization oven has the inner wall 2A that has the raw material feeding inlet opened, through which the raw material is fed, and forms a plurality of dry distillation chambers 2 of a multistage structure in the vertical direction and the outer wall 4 that surrounds the multistage dry distillation chambers 2 from the outside and forms the combustion chamber 3 that heats the dry distillation chamber 2. The outer wall 4 has the outer-opening window 300 for allowing the outside K of the outer wall 3 to communicate with the combustion chamber 3 and the outer-opening door 310 that can openably closes the outer-opening window 300. In a preferred embodiment, the inner wall 2A has the inner-opening window 400 allowing at least one of the dry distillation chamber 2 and the combustion chamber 3 to communicate with each other and opposing to the outer-opening window 300 and the openably closing door 410 for closing the inner-opening window 400.