Provided is a method for producing thermoplastic resin compositions, the method comprising the step of melt-blending (A) a thermoplastic elastomer composition, obtained by dispersing (ii) an acid anhydride-modified or epoxy-modified rubber in (i) an ethylene-vinyl alcohol copolymer, with (B-1) a resin composition comprising at least one resin selected from (i) unmodified polyamide resins and modified polyamide resins or (B-2) a thermoplastic elastomer composition obtained by dispersing (ii) an acid anhydride-modified or epoxy-modified rubber in (i) at least one resin selected from unmodified polyamide resins and modified polyamide resins. Said thermoplastic elastomer composition has excellent gas barrier properties and the decrease in gas barrier properties associated with fatigue has been reduced.