To supply the matter to be incinerated at the corner or the back of a combustion chamber with air, and besides, prevent the matter to be incinerated from sticking fast to the inwall of the combustion chamber, by providing the terminal of a fire lattice with an incline inclined inward of the fire lattice or a step higher than the face of the fire lattice.

A fire lattice 7 is installed between a combustion chamber 2 and an ash receiving chamber 3, and an incline inclined inward of the fire lattice 7 is made around the fire lattice 7, and the incline works the matter 8 for incineration to separate from the inwall 2a of the combustion chamber. Then, the matter 8 to be incinerated is cast in the combustion chamber 2 from the door 5a of the combustion chamber for incineration, whereupon air is let in the ash receiving room 3 from an air port 6, and it combusts the matter 8 for incineration in the combustion chamber 2 through a fire lattice 7, and it is discharged from a chimney 4 as combustion gas. At this time, it is so arranged that it gets space 7b to supply air to the matter 8 for combustion along the inwall 2a of the combustion chamber, even if ash 8 is accumulated along the inwall 3a of the ash receiving room 3. Hereby, it ceases to occur such a trouble that the matter 8 for incineration remains unburnt in used charcoal form.