To prevent the falling of a refractor for wear resistant use by lining the refractory for heat insulating use on the inner surface of a casing and covering the inner surface of the refractory with a large number of materials for wear resistant use which consist of a metal material having wear resistant in a panel state.

A putting hole 22 for a bolt 21 is previously bored in a required position of a casing 15 corresponding to a nut 20, and a through-hole 23 is formed in a required position of a refractory 17 for heat insulating use corresponding to the putting hole 22 and the nut 20. After refractories 17 for heat insulating use are lined, the bolt 21 is screwed in the nut 20 from the putting hole 22 of the casing 15, while abutting a material 19 for wear resistant use on the inner surface of the refractory 17 for heat insulating use so that the nut 20 fixed to the rear surface of the material 19 is embedded in the putting hole 23, to fit the material 19 to the inner surface of the refractory 17. Thereby, the material 19 is prevented from falling.