METHOD OF MANUFACTURING BIAXIALLY ORIENTED FILM, BIAXIALLY ORIENTED FILM, AND LIQUID CRYSTAL DISPLAY DEVICE EQUIPPED WITH BIAXIALLY ORIENTED FILM

PROBLEM TO BE SOLVED: To provide a method of manufacturing a biaxially oriented film with reduced display unevenness and deflection of an optical axis in the lateral direction of the film, and a liquid crystal display device equipped with the same.SOLUTION: The method of manufacturing a biaxially oriented film F3 includes that vertical stretching (X) and lateral stretching (Y) are sequentially performed on the film comprising a polypropylene resin. The lateral stretching (Y) has a step (Y1) (preheating step) of preheating the film at a preheating temperature equal to or above the melting point of the polypropylene resin, and a step (Y2) (lateral stretching step ) of laterally stretching the preheated film at a temperature lower than the preheating temperature at ≥2.55%/sec and ≤3.70%/sec distortion speed in the lateral direction.