To eliminate the discharge of carbon dioxide causing global warming by using oxyhydrogen gas as main fuel or auxiliary fuel for a burner to decrease the released heat capacity of combustion gas to easily cool in heating system by melting or incinerating waste with the burner.

Incineration ash from an incineration ash hopper 2 and a thermit reaction agent from a melting agent hopper 3 are respectively supplied to a reaction furnace 1 and are mixed and pushed into the furnace by a pusher 4. The incineration ash and the melting agent are heated by the burner 5 and at a point of time to reach the thermit reaction starting temp., the exothermic reaction is started. After that, the molten mixture of the incineration ash with the melting agent is stored in a slag reservoir 5 and falls down into waster to be solidified. At this time, a waste gas generated by heating with the burner is sent to a gas cooling chamber 8 through a waste gas pipe 7 and cooled with water shower. The cooled waste gas is sent to a bag filter 9 to remove dust contained in the water gas and is discharged to the air from a stack.