PURPOSE: To eliminate instantaneous diffusion of high pressure/high temperature gas containing dust from a slag hole and to hold a visual field of a monitoring camera by suppressing a pressure in a melting furnace of municipal refuse incinerated ash to constant.

CONSTITUTION: When incinerated ash is loaded in a melting furnace 1 from an incinerated ash feeder 2, the ash is continuously supplied from the feeder 2, charged by each small amount while being exposed with the atmosphere in the furnace at a high temperature of clattering feeling, an incinerated ash charging method is so controlled that a pressure in the furnace always falls in a range of -7(±3)mmH2O in such a manner that high pressure/high temperature gas in the furnace in an enclosure 14 is not diffused from a slag hole 10 due to instantaneous gasification of moisture and unburned content contained in the ash charged in the high temperature furnace, and a visual field of a monitoring camera 16 near the hole 10 is held.