The dope prepared from a mixture solvent and solid contents such as cellulose ester and additives is cast on a drum cooled to −5° C. to form a gel-like film. The gel-like film is peeled off from the drum. Tension of 60 kg/m is applied to the gel-like film in the widthwise direction thereof and the temperature of the gel-like film is kept 120° C., when the content of the solvent to the solid contents in the gel-like film is in a range of 100 wt. % to 20 wt. %. Further the gel-like film is dried to be a cellulose ester film having 40 μm thickness. The IR spectrum of the cellulose ester film has a peak in a range of 520 cm−1 to 480 cm−1 which indicates the crystallization of the polymer. The cellulose ester film has tear strength of 12 g, Rth of 42 nm and Re of 1.2 nm. As crystallization of the polymer proceeds, the cellulose ester film has sufficient strength and optical properties.