A power transmission device 2 in a non-contact power supply device 1 has: a transmission coil 14 that supplies power to a power reception device 3; and a power supply circuit 10 that supplies AC voltage having a switching frequency at which the transmission coil 14 does not resonate, to the transmission coil 14. A power reception device 3 has: a resonance circuit 20 having a reception coil 21 that receives power from the power transmission device 2 and a resonance capacitor 22 connected in parallel to the reception coil 21; a rectification circuit 24 that rectifies power output from the resonance circuit 20; and a coil 23 connected in series to the reception coil 21, between the resonance circuit 20 and the rectification circuit 24.