A method for forming a cover film includes applying a composition including a first polymer and a solvent on a surface of a base material to form a coating film. The base material includes a surface layer which includes a first region and a second region having a surface condition that differs from a surface condition of the first region. The coating film is heated. A portion of the coating film is desorbed with a rinse agent after the heating. The portion is formed on the second region of the coating film. The first polymer includes a first structural unit represented by formula (1), or includes a monovalent organic group which bonds to at least one end of a main chain of the first polymer and which includes a nitrogen atom.