A flame spraying burner melts or partially melts with combustion heat, a spray material comprising a powdered fire-resisting material to thermally spray a damaged portion of a furnace wall or the like. The flame spraying burner includes a burner nozzle body having a central passage for supplying oxygen-contained gas, the central passage having a projecting leading end, and a plurality of fuel gas supply passages formed around the central passage. Each of the plurality of fuel gas supply passages has a leading end recessed from the leading end of the central passage. A cylindrical burner tile is positioned around the leading end of the fuel gas supply passages and extends to at least the leading end of the central passage. A plurality of oxygen jetting ports are formed in the radial direction around the leading end of the nozzle cap.