Abstract: According to the present invention, provided is a thermoplastic elastomer composition, comprising an ethylene-propylene-nonconjugated diene ternary copolymer or an ethylene-propylene binary copolymer, a crystalline polyolefin resin, a non-aromatic softening agent, and an organic peroxide, in which the crystalline polyolefin resin has from 0.1 g/10 min. to 100 g/10 min. of melt flow rate which is measured in accordance with JIS K7210 under conditions of 230° C. and 21.18 N and is contained in an amount of from 10 to 150 parts by weight every 100 parts by weight of the copolymer; the non-aromatic softening agent has a kinetic viscosity of 300 mm2/s or more at 40° C. and is contained in an amount of from 20 to 150 parts by weight every 100 parts by weight of the copolymer; the organic peroxide is contained in an amount of from 0.1 to 10 parts by weight every 100 parts by weight of the copolymer; and hardness measured by a JIS type A durometer is from 30 to 70 degrees.