A rubber composition which contains a thermoplastic crosslinked product comprising 1-99 parts by weight of an ethylene-&agr;-olefin copolymer (A) containing an ethylene unit and an &agr;-olefin unit of 3-20 carbon atoms and prepared using a metallocene catalyst and 1-99 parts by weight of an olefin resin (B) (the total amount of (A) and (B) being 100 parts by weight), the crosslinking degree of (A) being not less than 50%, and 1-500 parts by weight of a thermoplastic elastomer (C) added later to the crosslinked product.