Foreign object detection device and foreign object detection method

The invention relates to a foreign matter detection device and method, and the device comprises a first detection unit which is parallel to a transmitting coil, is disposed in a coupling range of the transmitting coil, and is used for generating a first induction electric signal set according to an excitation magnetic field provided by the transmitting coil, the first induction electric signal set comprises a plurality of pairs of first induction signals and a pair of second induction signals; the control module is connected with the first detection unit and is used for judging whether foreign matters exist in the coupling range of the transmitting coil or not according to the first induction electric signal set; the first detection unit comprises a first detection coil group and a second detection coil group, a first center line of the second detection coil group coincides with a second center line of the transmitting coil, the first detection coil group is symmetrical about the first center line, and the fi