A power transmission device 2 for a non-contact power supply device 1 has a transmission coil 14 and a power supply circuit 10 that supplies, to the transmission coil 14, AC power having a switching frequency at which the transmission coil 14 does not resonate. In addition, a power reception device 3 for the non-contact power supply device 1 has: a resonance circuit 20 that has a reception coil 21 and a resonance capacitor 22 resonating in parallel and a first coil 23 connected in series or parallel to the reception coil 21; and a coil 23 connected in series to the reception coil 21.