The optical film is made of a cellulose ester film of which the retardation Ro of the in-plane direction is 40 to 100 nm and the retardation Rt of the thickness direction is 50 to 200 nm. In the production method of the optical film according to a solution casting film forming method, a cellulose ester solution (dope) is casted on a substrate, a film (web) is stripped from the substrate, thereafter, the film is stretched in the width direction (TD direction) and, at the same time, is stretched in the machine direction (MD direction) under such conditions that remaining solvent exists while being dried. Therein, the remaining solvent amount upon the stretching after the film (web) is stripped from the substrate is 5 to 10% and the relaxation contraction of the MD direction in the range of the TD direction stretching ratio(%)*0.1 to the TD direction stretching ratio(%)*0.3 is caused concurrently with the TD direction stretching.