A method and apparatus for removing dust from a base film effectively so that electrostatic charges of the base film are reduced while the cleaning effect is kept high. After a cleaning solvent is applied onto one surface of a base film by a precoater, a rod member is pressed against the base film while the cleaning solvent remains on the base film, so that deposits on the base film are separated and scraped together with the cleaning solvent from the base film by the rod member. Just after the deposits are scraped from the base member, a solvent, of the same kind as the cleaning solvent or a mixture of a solvent of the same kind as the cleaning solvent and an additive mixed thereto, is applied onto the base film while the surface of the base film coated with the cleaning solvent is not exposed to an atmospheric air space.