To prevent degradation of electrical characteristics caused by a resin filled between electrodes in an ultraviolet light-emitting operation, the present invention provides a base 10 that comprises an insulating base material 11 and two or more metal films 12 and 13 that are formed on one side of the insulating base material 11 and electrically separated from each other. The two or more metal films are formed to include an upper surface and a side wall surface that are covered by gold or a platinum group metal, to be capable of mounting thereon one or more nitride semiconductor light-emitting elements and the like, and to have, as a whole, a predetermined planar view shape including two or more electrode pads. On the one side of the base material 11, along a boundary line between an exposed surface of the base material 11 that is not covered by the metal film 12, 13 and a side wall surface of the metal film 12, 13, at least a first part of the exposed surface of the base material 11 continuous with the boundary line that is sandwiched between two adjacent electrode pads and the side wall surfaces of the metal films 12 and 13 that oppose to each other with the first part interposed therebetween are covered by a fluororesin film 16, and a part of an upper surface of the metal film 12, 13 that composes at least the electrode pad is not covered by the fluororesin film 16.