A contactless power transmission device includes: a plurality of power transmission coil units; a plurality of detection units configured to detect a foreign substance on and around each power transmission coil unit; a communication unit configured to communicate with a vehicle; and a control unit configured to select one of the plurality of power transmission coil units based on information about a mounting position of a power reception device from the vehicle obtained by the communication unit, and to guide, when a detection unit detects a foreign substance at the selected power transmission coil unit, the vehicle toward a power transmission coil unit different from the selected power transmission coil unit, before the vehicle stops. This can prevent a reduction in power transfer efficiency due to a foreign substance or the like in a power transmission device including a plurality of power transmission coils.