The present invention provides a transparent optical film that has excellent optical characteristics for realizing the uniform retardation distribution and restraining rainbow-colored irregularities. The optical film, which is obtained by laminating a birefringent layer (a) on a transparent film (b), satisfies all the following formulae (I), (II) and (III). .DELTA.n(a)>.DELTA.n(b).times.10 (I) 1<(nx-nz)/(nx-ny) (II) 0.0005.ltoreq..DELTA.n(a).ltoreq.0.5 (III) In the above formulae (I), (II) and (III), .DELTA.n(a) and .DELTA.n(b) denote respectively birefringent indexes of the birefringent layer (a) and the transparent film (b). The signs of nx, ny and nz indicate refractive indexes in an X-axis direction, a Y-axis direction and a Z-axis direction in the birefringent layer (a), respectively. The X-axis corresponds to an axial direction exhibiting a maximum refractive index within a plane of the birefringent layer (a), the Y-axis corresponds to an axial direction perpendicular to the X-axis within the plane, and the Z-axis corresponds to a thickness direction perpendicular to the X-axis and the Y-axis.