To obtain a water-resistant polarizing film free from deterioration in dichroic ratio caused by water-resistant treatment, it is critical that adjacent sulfonic acid groups or sulfonate groups in the organic dyes to be used for the polarizing film are spaced at moderate intervals. In a process for producing a water-resistant polarizing film of the present invention, the polarizing film before water-resistant treatment includes an organic dye which comprises an azo compound 20 represented by the following general formula (2)