High frequency electric wire

A high frequency electric wire 6 is provided in such a manner that a large number of wires 7 are bundled, twisted and insulated with an outer sheath S. Each wire 7 has an extra-fine hollow pipe structure of a capillary shape. The wire 7 is provided to make its hollow section 8 with the extra-fine hollow pipe structure an air cavity 9 or to cause its hollow section 8 to house an insulating material 10. In the latter case, the wire 7 is provided to cause a metal conductor to adhere to the outer periphery of an extra-fine insulating yarn which serves as the insulating material 10 by plating or vapor- deposition. The electric wire 6 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 6 fulfills its function to suppress and reduce an increase of the alternating current resistance due to a high frequency alternating current.