To provide a method for manufacturing an optical film which, when a solidification preventing liquid is made to flow down to both ends of a dope outlet, suppresses the scattering of the solidification preventing liquid into a pressure-reducing chamber, does not adhere to a cast film, suppresses skin spreading to both ends of the dope outlet, and has a surface good in plane properties, the optical film manufactured by using the method, a polarizing plate using the optical film, and a display.

The method for manufacturing the optical film has a supply process for supplying a resin dissolving liquid to both ends in the longitudinal direction of the dope outlet. In the supply process, the liquid is made to flow down from a plurality of openings of a supply member having the plurality of openings.