In view of the above-discussed state of the art, it is an object of the present invention to provide a method of coating an electric wire by which insulated wires excellent in dielectric breakdown voltage can be obtained by a relatively short period of dipping of articles to be coated in an electrodeposition bath. A method of coating an electric wire comprising cationic electrocoating with a cationic electrodeposition coating composition, wherein the cationic electrodeposition coating composition contains a resin composition having a hydratable functional group reducible directly by an electron and results in forming passive coat.