The present invention relates to an optical film that is excellent in optical properties and can be produced at low cost. In the optical film formed by laminating a transparent polymer film layer and a birefringent layer of a non-liquid crystalline polymer, the birefringent layer satisfies a condition represented by nx.gtoreq.ny>nz and the in-plane retardation of the transparent polymer film layer is 50 nm or less. In the above formula, nx, ny and nz are the refraction indices in the X-, Y- and Z-axes directions of the birefringent layer, respectively. The X-axis direction is the axial direction in which the refraction index shows a maximum value in the in-plane direction of the birefringent layer, the Y-axis direction is the axial direction perpendicular to the X-axis direction in the plane, and the Z-axis direction is the thickness direction perpendicular to the X- and Y-axes directions.