To provide a technology for generating a data base image of a road surface along a traveling route of a vehicle.

An image processor acquires the position information of an own vehicle 1 when a photographed image by a monocular camera 3 is acquired by a background image acquiring means 6a is acquired by a position information acquiring means 6b and then has the data base image of the road surface with a continuous road surface region which is generated by connecting upward view images excluding obstacles in which photographed images for respective frames are projection-transformed by a generating means 6d based on the position information for the own vehicle 1 by the position information acquiring means 6a. Therefore, since the data base image of the road surface is generated based on the photographed images by the monocular camera 3 of the own vehicle 1 during traveling, the data base image for the road surface along the traveling route of the own vehicle 1 can be generated from the photographed images that are photographed by the monocular camera 3, for example, while commuting.