THERMOPLASTIC ELASTOMER COMPOSITION

A thermoplastic elastomer composition including (a) a halogenated isoolefin para-alkylstyrene copolymer, (b) a modified rubber having an acid anhydride group, (c) a polymer component including an ethylene-vinyl alcohol copolymer, (d) a processing aid comprising an alkaline earth metal salt of a higher fatty acid, and (e) a crosslinking agent, the thermoplastic elastomer composition characterized in that the weight ratio (W a ) of the halogenated isoolefin para-alkylstyrene copolymer (a) in elastomer components ((a) + (b)) is 5-60 wt%, the weight ratio (W b ) of the modified rubber (b) having an acid anhydride group in the elastomer components ((a) + (b)) is 95-40 wt%, and the content (W d ) of the processing aid (d) comprising an alkaline earth metal salt of a higher fatty acid is 0.3-30 parts by mass with respect to 100 parts by mass of the halogenated isoolefin para-alkylstyrene copolymer (a).