According to the present invention, there is provide a coated film that can be highly prevented from suffering from deposition of oligomers from a surface of the film when exposed to a high temperature condition, and is excellent in adhesion property to various functional layers. The present invention relates to a coated film comprising a single-layer polyester film having an ester cyclic trimer content of not more than 0.7% by weight or a multilayer polyester film comprising a polyester surface layer having an ester cyclic trimer content of not more than 0.7% by weight, and a coating layer formed on at least one surface of the single-layer polyester film or multilayer polyester film, the coating layer being prepared from a coating solution comprising a crosslinking agent in an amount of not less than 70% by weight based on the weight of nonvolatile components in the coating solution.