A wiring member, comprising: a conductor (1, 1a, 1b); and an insulating layer (2, 2a, 2b) which covers the conductor (1, 1a, 1b), wherein the conductor (1, 1a, 1b) includes circuit wiring disposed on a substrate or an electric wire, and wherein the insulating layer (2, 2a, 2b) comprises an insulating material, comprising: a composite resin material comprising an organic resin and minute particles containing a metal element, wherein the organic resin comprises a resin material comprising polyester as a main backbone thereof and having an alkoxy group bound to the main backbone, and the minute particles have an average particle size of greater than or equal to 0.5 nm but less than or equal to 50 nm, wherein the organic resin comprises at least one resin material selected from a resin material group consisting of a cyclic olefin resin, and a polyetherimide resin, and wherein the average particle size of the metal element-containing minute particles is determined through image analyses of a section photograph taken by a transmission electron microscope or scanning transmission electron microscope (STEM), or analyses of profile data obtained by measurement using the small angle X-ray scattering method. a conductor (1, 1a, 1b); and an insulating layer (2, 2a, 2b) which covers the conductor (1, 1a, 1b), wherein the conductor (1, 1a, 1b) includes circuit wiring disposed on a substrate or an electric wire, and wherein the insulating layer (2, 2a, 2b) comprises an insulating material, comprising: a composite resin material comprising an organic resin and minute particles containing a metal element, wherein the organic resin comprises a resin material comprising polyester as a main backbone thereof and having an alkoxy group bound to the main backbone, and the minute particles have an average particle size of greater than or equal to 0.5 nm but less than or equal to 50 nm, wherein the organic resin comprises at least one resin material selected from a resin material group consisting of a cyclic olefin resin, and a polyetherimide resin, and wherein the average particle size of the metal element-containing minute particles is determined through image analyses of a section photograph taken by a transmission electron microscope or scanning transmission electron microscope (STEM), or analyses of profile data obtained by measurement using the small angle X-ray scattering method. a composite resin material comprising an organic resin and minute particles containing a metal element, wherein the organic resin comprises a resin material comprising polyester as a main backbone thereof and having an alkoxy group bound to the main backbone, and the minute particles have an average particle size of greater than or equal to 0.5 nm but less than or equal to 50 nm, wherein the organic resin comprises at least one resin material selected from a resin material group consisting of a cyclic olefin resin, and a polyetherimide resin, and wherein the average particle size of the metal element-containing minute particles is determined through image analyses of a section photograph taken by a transmission electron microscope or scanning transmission electron microscope (STEM), or analyses of profile data obtained by measurement using the small angle X-ray scattering method.