An object of the invention is to satisfy all of a high-density wiring package, soldering thermal resistance, an insulating property and high-frequency transmission characteristics. The invention is a multi-layer wiring substrate having a lamination of a plurality of dielectric layers which are each provided with a wiring conductor made of a metallic foil on at least one of upper and bottom surfaces of the dielectric layer, the wiring conductors between which the dielectric layer is disposed being electrically connected with each other via a through conductor formed in the dielectric layer; on this occasion, the dielectric layers each individually are composed of a liquid crystal polymer layer and cladding layers made of a polyphenyleneether-type organic substance and formed on upper and bottom surfaces of the liquid crystal polymer layer.