To provide a method for discharging an incineration residue in a waste incinerator, a device therefor and the waste incinerator which are so contrived that the dust to be discharged from the incinerator is sterilized and then discharged.

An opening-closing mechanism comprised of an upper gate 18 and a lower gate 24 is provided in a discharging part for the incineration residue in the wastes incinerator and the inside-furnace side and the outside- furnace side of the discharging part are partitioned off by the mechanism. High-temperature gas or vapor is introduced into an incineration residue stagnation part partitioned off by the mechanism and unburned wastes in the incineration residue in this part are thereby sterilized and then discharged outside the furnace.