A retardation film of the present invention comprises a stretched film of
a polymer film containing a norbornene-based resin, wherein the stretched
film satisfies the following equation (1) and the equation (2); 100
nm.ltoreq.(nx-ny)d.ltoreq.350 nm . . . (1),
0.1.ltoreq.(nx-nz)/(nx-ny).ltoreq.0.9 . . . (2), where the refractive
indices in the slow axis direction, the fast axis direction and the
thickness direction of the film are nx, ny and nz, respectively, d(nm) is
thickness of the film, and the slow axis direction is a direction that
the refractive index in film plane is maximum. The retardation film is
hard to cause a shift or an unevenness of a retardation value due to a
stress.