Carbonized material production kiln

A carbonized material production kiln including an open ceiling surface, side walls at four faces being in a quadrangular shape, an exhaust space which is formed between an iron plate with a vent hole opened that is laid as a kiln floor in a state of being enclosed by the side walls and a kiln bottom surface and through which exhaust gas discharged as a result of carbonization of a raw material for carbonization, a combustion device being made to communicate with the discharge space and for combusting exhaust gas, and a stage which is continuous to at least one side wall of the side walls and on which a traveling work machine can travel at the same height as that of an upper surface of the side wall, the side wall is formed by stacking blocks each being in a cubic shape and made of concrete without reinforcing iron in plural numbers horizontally and vertically to thereby make an exposed surface on the kiln side wall changeable by recombination of a block surface, and in the exhaust space between the iron plate of the kiln floor and the kiln bottom surface, a heat storage/retention member is filled in a ventable state.