A noncontact power supplying system transfers power by noncontact between a ground power supplying apparatus and a vehicle. The vehicle includes a power reception side resonance circuit for receiving power, and a signal emitting device for emitting an alternating magnetic field or electric wave for transmitting vehicle identification information of the vehicle to the ground power supplying apparatus. The ground power supplying apparatus includes a power transmission side resonance circuit for transmitting power to the power reception side resonance circuit, and a signal reception device for receiving an alternating magnetic field or electric wave emitted from the signal emitting device. The ground power supplying apparatus detects a relative positional relationship between the power transmission side resonance circuit and the power reception side resonance circuit, based on the strength of the alternating magnetic field or electric wave which the signal reception device receives.