To highly accurately prevent uneven drying of a coating film, relating to a method for drying the coating film and an apparatus therefor and an optical film using the same.

The method is provided for drying the coating film that has been formed by applying the coating liquid to a traveling long web 12, by forming a tunnel-shaped drying zone 26 so as to surround the web 12, and supplying drying air into the drying zone 26 from rectangular air-supplying nozzles 34A-34G which faces to the drying zone 26, wherein among layer components of the drying air which is supplied from the air-supplying nozzles 34A-34G, a boundary layer component which flows in the vicinity of the inner wall surface 37a of the air-supplying nozzle 34A-34G and is supplied from the nozzle cannot hit the surface of the coating film, while there are the boundary layer component and a central layer component which flows in a central part of the air-supplying nozzle 34A-34G and is supplied from the nozzle.