In order to prevent deterioration in electrical characteristics caused by a resin filled in between electrodes, during ultraviolet light-emitting action, provided is a base 10 comprising an insulatingbase material 11 and at least two electrically isolated metal films 12, 13 formed upon one surface of the base material 11. The metal films have an upper surface and side wall surfaces thereof coatedin gold or a platinum-group metal. The base is formed in a prescribed shape in the planar view, including overall the at least two electrode pads, such that at least one nitride semiconductor light-emitting element, etc., can be mounted thereto. Along a boundary between an exposed surface of the base material 11 not covered by the metal films 12, 13 and the side wall surface of the metal films 12, 13, upon one surface of the base material 11, at least a first section sandwiched between two adjacent electrode pads on the exposed surface of the base material 11 continuing from the boundary andthe side wall surface of the metal films 12, 13 facing across the first section are covered by a fluorine resin film 16 and a location constituting at least an electrode pad on the upper surface of the metal films 12, 13 is not covered by the fluorine resin film 16.