To reduce running cost and maintenance cost by eliminating the need of operation by a person having a special skill by cooling by means of an air-cooled wall an inner wall constituting a combustion melting furnace body.

An air cooled wall 24 of a combustion melting furnace 7 includes an inner wall 23 comprising a refractory material, a double pipe outer wall 36 surrounding the inner wall 23, and a partition wall 37 coupling longitudinally between the inner wall 23 and the outer wall 36 and provided radially, to form a plurality of annular air passages 27 exteriorly of the inner wall 23. A heat insulation layer is provided outside the outer wall 36 to heat-insulate the entire of the combustion melting furnace 7. Hereby, the inner wall 23 constituting the body of the combustion melting furnace 7 is cooled by air (h) flowing in the plurality of the air passages 27, and the amount of air flowing through each air passage 27 is made uniform so that it is uniformly cooled. Accordingly, there is eliminated the need of operation by a person having a special skill, and hence there are reduced the running cost and the maintenance cost.