Provided is a thermoplastic elastomer composition excellent in mechanical characteristics, abrasion resistance, etc., comprising: a crosslinked composition (X) obtained by heat-treating, under molten condition, a composition containing 100 pars of a block copolymer or a hydrogenated product thereof, the block copolymer including a polymer block A mainly derived from an aromatic vinyl compound containing 1% by mass or more of an alkylstyrene and a polymer block B mainly derived from a diene compound, 10 to 300 parts of an olefin-based resin, 0.01 to 20 parts of a crosslinking agent, 1 to 50 parts of a crosslinking adjuvant, and 30 to 250 parts of a softener for rubber; and a hydrogenated block copolymer (Y) obtained by hydrogenating a block copolymer having at least two polymer blocks of an aromatic vinyl compound and at least one polymer block of a conjugated diene compound, with the mass ratio of (X)/(Y)=10/90 to 90/10.