The present invention relates to a novel thermoplastic elastomer composition with superior oil resistance along with elastomeric flexibility, creep resistance at high temperature, superior mechanical strength and moldability. The composition comprises (a) 100 parts by weight of a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least two A polymer blocks comprised mainly of a vinyl aromatic compound and at least one B polymer block comprised mainly of a conjugated diene compound; and (b) 30-300 parts by weight of a partially crosslinked thermoplastic elastomer obtained by polymerizing an acrylate monomer absorbed in a polyolefin. The novel composition can be applied as a material for various molded parts.