An oriented thermoplastic elastomer film having reduced permeability and improved fatigue resistance comprising a dynamically vulcanized polymer blend of (A) a halogenated isobutylene elastomer and (B) polyamide, the film is produced by casting or blowing the above polymer blend under the condition such that a shear rate at a die lip for casting or blowing is regulated to control the molecular arrangement in the film, whereby the planar birefringence (PBR) of the resultant film becomes greater or equal to 0.002 and a production process of the same.