Abstract: A waste melting furnace has a coke layer formed therein, and an annular combustion space formed circumferentially of the coke layer below an upper surface thereof and communicating with the coke layer. A depending wall projects downwardly from an upper position of the combustion space to mark a boundary between the combustion space and the coke layer. A waste is fed in powder form into the combustion space, and burned in the combustion space and the coke layer to be melted and slagged. The depending wall prevents the waste from passing directly into exhaust gas, and causes the waste to remain in the combustion space for a prolonged time before flowing into the coke layer.