An optical film which has Re(.lamda.) and Rth(.lamda.) fulfilling the following two formulae: 0.ltoreq.Re.sub.(590).ltoreq.10 |Rth.sub.(590)|.ltoreq.25 wherein Re(.lamda.) is a retardation value in plane (nm) at a wavelength of .lamda. nm; and Rth(.lamda.) is a retardation value in film thickness direction (nm) at a wavelength of .lamda. nm.