A steam barrier film comprising at least one inorganic gas barrier layer on a polyalkylene naphthalate resin substrate film in which the glass transition temperature (Tg) of the polyalkylene naphthalate resin is from 70 to 150.degree. C. and the steam barrier film comprises at least one conductive layer with a resistance of 10.sup.12 .OMEGA. or less at 25.degree. C. and 60% relative humidity.