Provided is a production method for a thin birefringent film with a
satisfactory alignment property, in which a refractive index is
controlled three-dimensionally and optical properties are unlikely to
decrease in the case where the birefringent film is placed under high
temperature and high humidity. The production method for a birefringent
film of the present invention includes: the step (1) of preparing a
solution that exhibits a nematic liquid crystal phase, containing at
least one kind of polycyclic compound containing a --SO.sub.3M group
and/or a --COOM group (M represents a counter ion) and a solvent; the
step (2) of preparing a base material at least one surface of which is
subjected to a hydrophilization treatment; and the step (3) of applying
the solution prepared in the step (1) to the surface of the base material
prepared in the step (2), the surface being subjected to the
hydrophilization treatment, followed by drying, in which a contact angle
of water at 23.degree. C. on the surface of the base material prepared in
the step (2), the surface being subjected to the hydrophilization
treatment is 45.degree. or less.