Integrated processing unit captures range images shot by CCD cameras which are respectively provided on front, rear, left and right sides of a vehicle and image processor. Location-allocation unit creates a location-allocation model of an obstacle from the range images and road surface images (heights of images above road surface). Vehicular swept path calculating unit calculates a swept path of each representative point. Collision decision calculates intersection of the obstacle of the location-allocation model with the swept paths of the representative points and judges whether the points cross the obstacle. When a representative point may possibly cross the obstacle, the point is enhanced and displayed together with the obstacle (object) on monitor.