A power feeding coil that configures a non-contact power feeding system is provided. The power feeding coil is provided with a coil through which an AC current of a specific frequency flows, and a core that forms a section of a circulating magnetic path, which is interlinked with the coil. In the coil, a wire having an insulating covering is wound around a conductor, and a covering thickness of the insulating covering is set so that the influence of a proximity effect that occurs at the specific frequency between adjacent portions of the wire is a predetermined amount or less. According to this configuration, it is possible to freely adjust a separation distance between portions of the conductor by altering the covering thickness; and the occurrence of AC loss caused by a proximity effect may be appropriately suppressed.