A thermoplastic elastomer composition which comprises (A) a thermoplastic resin, (B) a halogenated isoolefin/para-alkylstyrene copolymer rubber, and (C) a thermoplastic elastomer, wherein the thermoplastic resin (A) forms a continuous phase, the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) and the thermoplastic elastomer (C) have been separately dispersed in the continuous phase, the halogenated isoolefin/para-alkylstyrene copolymer (B) has been crosslinked, the thermoplastic elastomer (C) has not been crosslinked, and the amount of the thermoplastic elastomer (C) is 20-50 mass% with respect to the total amount of the halogenated isoolefin/para-alkylstyrene copolymer rubber (B) and the thermoplastic elastomer (C).