1. A vehicle periphery monitoring device comprising: a first image processing component configured to extract an image area corresponding to an object as an object area from an image of a periphery of a vehicle acquired by an imaging device mounted in the vehicle; and a second image processing component configured to display an output image representing the periphery of the vehicle in accordance with the image on an image display device mounted in the vehicle, wherein the second image processing component is configured to display an enlarged image of the object on the image display device in such a way that the enlarged image of the object overlaps with the output image but does not overlap with the object contained in the output image on the proviso that the object area is extracted by the first image processing component.