The invention relates to an optical compensation film for IPS or FFS-mode liquid crystal display devices, having the tilt angle β[°] not equal to zero, β[°] being defined as φ giving the minimum value of retardation R[φ] which is retardation measured for incident light coming in a direction tilted by φ° from a normal line relative to the film-plane, the direction being in a plane including the direction perpendicular to the in-plane slow axis thereof and the normal line; and having retardation along the thickness direction at a wavelength of 550 nm, Rth(550), not equal to zero.