Provided is a non-contact power supply device which detects foreign objects interposed between a power transmission coil and a power receiving coil. This non-contact power supply device is provided with a second coil which contactlessly transmits power to or receives power from a first coil at least by means of magnetic coupling, multiple sensors for detecting position shifts between the first coil and the second coil, a position detection means which, on the basis of the output values of the sensors, detects the relative positions of the first coil and the second coil, and a foreign object detection means which compares the output values of the sensors and from these comparison results detects foreign objects between first coil and the second coil.