PURPOSE: To obtain a plastic substrate with high aging resistance and stability by forming an oriented film on a thin film contg. essentially a composite of a metal belonging to the IIIb, IVa or IVb group in the periodic table.

CONSTITUTION: A thin film 2 contg. essentially a composite of a metal belonging to the IIIb, IVa or IVb group in the periodic table such as Al, Zr or Ge, e.g., an alkoxy compound, a halogen compound or a chelate compound of the metal is formed on a plastic substrate 1 of polyethylene terephthalate or the like having a laid electrically conductive transparent film. On the thin film 2 an oriented film 3 made of linear polyamide, satd. polyester, thiokol, the reaction product of epoxy resin and/or isocyanate resin with linear polyamide, satd. polyester or thiokol, an org. silane compound, polybutadiene, polyisoprene or the like is formed.