Disclosed is a wiring member comprising a sheet-like porous substrate provided with a large number of open-cells which are three-dimensionally branched and opened to a first major surface as well as to a second major surface of the porous substrate, and a conductive portion formed on the first major surface of the porous substrate and formed at least partially an inter-penetrating structure together with the porous substrate at an interface of the porous substrate. The apertures of the open-cells on the first major surface have an average diameter and an average number of the apertures, at least one of which is smaller than that of the second major surface.