In the case of the expansion-molded article 1 further having the skin layer 14 on the outer surface of the resin layer 13, examples of a resin or polymer (hereinafter referred to as resin simply) used for forming the skin layer 14 include thermoplastic resins, such as polyethylene resins such as low density polyethylene, high density polyethylene and linear low density polyethylene; polypropylene