PURPOSE: To make it easy to discharge combustion ashes by a method wherein the titled ash discharge box is provided at the lower part of an incinerator or a boiler.

CONSTITUTION: An ash discharging box 5 which is capable of being drawn freely is provided under a rooster 3 located at the lower part of an incinerator body 1 having a fuel inlet port 2 in the periphery of a side wall and an air supply port 4 at the lower part thereof. The size of the ash discharging box 5 is so determined that the box has a capacity to cover the amount of ashes produced in a single day. With the provision of such box, the discharge of the combustion ashes after or prior to the use of the incinerator can be performed easily and in a short time by drawing out the box from the incinerator.