POWER TRANSMITTING DEVICE, POWER RECEIVING DEVICE, AND POWER TRANSMISSION SYSTEM

A power transmission device (41) for use in a power transfer system in which resonance through an electromagnetic field is used includes a power-transmission-side electromagnetic induction coil (23), a power-transmission-side resonance unit (28), and a power-transmission-side shield unit (51) surrounding the power-transmission-side electromagnetic induction coil (23) and the power-transmission-side resonance unit (28). The power-transmission-side electromagnetic induction coil (23) and the power-transmission-side resonance unit (28) are disposed in an identical plane.