A method of producing a film is provided. The film includes a base material layer which is shrunk by heat and a functional layer which is dried while being restricted by the base material layer. The method involves heating the film while applying a tensile force in a direction of a length of the film so as to convey the film, and subjecting the film to a heat treatment while, in a distribution along a width of the film, a center part is higher in temperature than end parts. A center part sample of the film is smaller in curling amount with respect to the width of the film than an end part sample, or a standard deviation in curling amount with respect to the width is not more than 1 mm between two samples from respective end parts and a sample from the center part of the film.