A power transmission system that includes a power transmitting device and a power receiving device. The power transmitting device includes a high-frequency voltage generator, a piezoelectric resonator, a power transmitting device side passive electrode, and a power transmitting device side active electrode. The power receiving device includes a piezoelectric resonator, a load, a power receiving device side passive electrode, and a power receiving device side active electrode. The active electrode of the power transmitting device and the active electrode of the power receiving device are in proximity with each other, whereby the power transmitting device and the power receiving device are capacitively coupled through the active electrodes and the surrounding dielectric medium.