A periphery monitoring device according the embodiment comprising: a first storage that stores therein road surface information in a moving direction of a vehicle including a plurality of wheels; a controller that generates underfloor information on an underfloor region of the vehicle from the road surface information, the underfloor region including at least part of a region of all the wheels; a second storage that is nonvolatile and stores therein the underfloor information when the vehicle ends driving; and a display that displays the underfloor information when the vehicle starts driving.