To obtain a film being used suitably for a liquid crystal display device, being homogenious optically, causing little distortion of an image and being excellent in handling properties in secondary processing.

An optical film of which the ratios (direction of MD/direction of TD) of flex fatigue resistances and tensile strengths in the directions of a machine axis (directions of MD) and the directions of a width axis (direction of TD) are within the range of 0.9-1.1, is provided. A biaxially oriented optical film of which the ratio (direction of MD/direction of TD) of percents of orientation in the direction of MD and the direction of TD is preferably within the range of 0.85-1.20, is provided.