There is provided a method for manufacturing a thin polarizing film having an absorption axis oblique to a width direction of the film which comprises the steps of: performing an orientation treatment in two directions in a plane of a support film; applying a solution containing a lyotropic liquid crystal compound onto a surface of the support film; and causing a column-shaped aggregate of the lyotropic liquid crystal compound to be oriented in a direction (orientation direction) equal to the vector sum of a direction of first orientation treatment and a direction of second orientation treatment.