To stably incinerate to melt waste by disposing it without separating it into incombustible material and combustible material.

This melting furnace 1 comprises a melting furnace body 2, a waste supply unit 4 provided at the body 2 to introduce waste 3 into the furnace, a heating means 5 used to incinerate to melt the waste 3 at the body 2, a plurality of heat resistant balls 6 provided in the body, a tap part 7 provided in a lower part of the body 2 to externally exhaust molten material 3, and an exhaust gas outlet 13. The waste 3 is incinerated to be molten on the balls 6.