A steel cord has a stranded structure comprising a plurality of sheath strands intertwined around the outer circumferential surface of a core strand; and a filament having a linear mass density of at least 560 dtex and not more than 2,200 dtex wrapped in a spiral around the outer circumferential surface of the core strand. The steel cord is embedded in an unvulcanized rubber member to mold a molded rubber article, which is then vulcanized.