A wireless power transmission system includes a power-supplying device including an electronic oscillator that generates electric power having a frequency of 1 MHz or more and 5 MHz or less, and a power-supplying coil member in which the electric power flows; and a power-receiving device including a power-receiving coil member that is capable of generating electric power based on the magnetic field generating from the power-supplying coil member, wherein the power-receiving coil member is a sheet coil including an insulating layer and a first coil pattern disposed at one side of the insulating layer, the first coil pattern is composed of wires, and the wires are disposed in spaced apart relation from each other with a predetermined space provided therebetween in the radial direction of the first coil pattern.