A portable gas burner in which the base is comprised of a hollow disk-like shell and a plurality of sector plates detachably fastened to one another and to the periphery of the disk-like shell by screws; the reflector is comprised of a reflector disk and a plurality of sector plates detachably fastened to one another and to the periphery of the reflector disk by screw rods and wing nuts, which screw rods being respectively formed integral with the sector plates of the reflector.