Abstract: OBJECT: To provide a non-contact power supply apparatus capable of supplying stable power very efficiently even when changes in load at the receiving side occur by tuning AC frequency supplied to the oscillating circuit on the receiving side and the resonant frequency of the resonance circuit on the receiving side. CONSTITUENTS: At the receiving side is provided a resonance circuit 3 in which resonance coil L3 on the receiving side is connected in parallel with resonance capacitor C3. At the supplying side are provided a detecting coil L2 which detects resonant frequency of resonance circuit 3 on the receiving side and a control means 1 which tunes AC frequency supplied to the aforementioned oscillating circuit 2 on the supplying side with resonant frequency of the aforementioned oscillating circuit 3 on the receiving side according to the frequency of induced electromotive force detected by said detecting coil L2.