still object map generation means for repeatedly generating a still object map indicating a relative position of a still object with respect to the vehicle by extracting the still object based on information indicative of a position and a speed of an object detected by the radar means, the still object map being segmentalized to define unit regions for the still object map;

evaluation value setup means for, each time the still object map is generated, providing each unit region for the still object map with an evaluation value being positive for a unit region containing a still object and being negative for a unit region not containing a still object;

evaluation map creation means for obtaining an accumulated evaluation value by totaling evaluation values repeatedly provided to each unit region for the still object map to thereby create an evaluation map, which is segmentalized to define unit regions for the evaluation map, wherein the unit regions for the evaluation map are individually associated with the unit regions for the still object map, such that a unit region for the evaluation map indicating high possibility of presence of the still object contains a large accumulated evaluation value; and

road shape recognition means for recognizing a road shape based on an evaluation map created by the evaluation map creation means.