A high frequency electric wire is provided in such a manner that a large number of wires are bundled, twisted and insulated with an outer sheath S. Each wire has an extra-fine hollow pipe structure of a capillary shape. The wire is provided to make its hollow section with the extra-fine hollow pipe structure an air cavity or to cause its hollow section to house an insulating material. In the latter case, the wire is provided by causing a metal conductor to adhere to the outer periphery of an extra-fine insulating yarn, which serves as the insulating material, by plating or vapor-deposition. The electric wire is used as a circuit cable or a coil in a non-contact power feeding device which supplies power based on a mutual induction action of the electromagnetic induction. In this manner, the electric wire fulfills its function to suppress and reduce an increase of the alternating current resistance due to a high frequency alternating current.