Abstract: Disclosed is a polarizing film containing a base resin and a photodichroic material which is characterized in that (1) the uniaxial orientation coefficient (f) of the principal crystal axis which is a crystal axis parallel to the molecular chain of the base resin, with respect to the reference axis is not less than 0.7 and (2) when a specimen of the polarizing film is cut out so as to have a surface perpendicular to the reference axis and X-rays impinging on the specimen parallel to the reference axis, the product (f.times.R) of the aforesaid uniaxial orientation coefficient (f) and the proportion (R=(I.sub.min /I.sub.max).times.100) of the minimum value (I.sub.min) to the maximum value (I.sub.max) of diffracted X-ray intensity on the resulting Debye-Scherrer ring is not less than 10. This polarizing film has excellent thermal resistance and moisture resistance and gives a high degree of polarization.