Abstract: Provided is an optical film used for the optical compensation, in which additives are added to thereby have a good stability at high temperature and high humidity, a higher chromaticity, a higher Haze and a higher moisture resistance, as well as a small thickness direction retardation (Rth).

Abstract: A process for producing a cellulose ester film that is produced by a melt casting method using no solvent at film formation, and that attains reduction of bright spot foreign matter, excelling in planarity, and that attains reduction of staining, excelling in dimensional stability. It is also intended to provide such a cellulose ester film, a polarizing plate and a liquid crystal display unit. There is provided a process for producing a cellulose ester film, characterized by forming into a film a material containing a cellulose ester and an ester compound of 1 to 7.5 distribution coefficient obtained by condensation of a polyhydric alcohol and an organic acid of the general formula: (1) according to a melt casting method.