A road face position information detection apparatus (120, 102) for a vehicle moving on a road face, the vehicle equipped with a plurality of image capturing units for capturing a plurality of images of a forward area in a moving direction of the vehicle, road face information detectable using the plurality of captured images, the road face information detection apparatus (120, 102) comprising: a parallax information generation unit (121, 131, 132) configured to generate parallax information based on the plurality of captured images; a V map generation unit configured to generate a V map indicating a frequency profile of parallax values in each horizontal line of the captured image, based on the parallax information; a road face shape detection unit configured to detect points on the V map having a frequency exceeding a given frequency threshold and indicating a feature that parallax values become smaller as closer to the upper part of the captured image as road face candidate points based on the V map by searching a range the center of which is determined by the road surface candidate points detected on the V map generated from the captured image in a previous frame, and to conduct linear approximation processing for the road face candidate points to obtain an approximated straight line on the V map; and a road face information detection unit configured to detect position information including height information of the road face based on a detection result of the road face shape detection unit, wherein the height information is obtained by comparing the approximated straight line output from the road face shape detection unit with a reference straight line corresponding to a virtual reference road face obtained by extending a face of a road face parallel to the road face right below the vehicle to ahead of the vehicle, characterized in that the road face shape detection unit, within a frequency profile of parallax values indicated by the V map, is further configured to determine a maximum frequency of parallax values existing in a portion of the captured image that is lower than a profile portion of parallax values determined for the approximated straight line for the previous frame as the given frequency threshold, and to determine the road face candidate points using the determined frequency threshold. a parallax information generation unit (121, 131, 132) configured to generate parallax information based on the plurality of captured images; a V map generation unit configured to generate a V map indicating a frequency profile of parallax values in each horizontal line of the captured image, based on the parallax information; a road face shape detection unit configured to detect points on the V map having a frequency exceeding a given frequency threshold and indicating a feature that parallax values become smaller as closer to the upper part of the captured image as road face candidate points based on the V map by searching a range the center of which is determined by the road surface candidate points detected on the V map generated from the captured image in a previous frame, and to conduct linear approximation processing for the road face candidate points to obtain an approximated straight line on the V map; and a road face information detection unit configured to detect position information including height information of the road face based on a detection result of the road face shape detection unit, wherein the height information is obtained by comparing the approximated straight line output from the road face shape detection unit with a reference straight line corresponding to a virtual reference road face obtained by extending a face of a road face parallel to the road face right below the vehicle to ahead of the vehicle, characterized in that the road face shape detection unit, within a frequency profile of parallax values indicated by the V map, is further configured to determine a maximum frequency of parallax values existing in a portion of the captured image that is lower than a profile portion of parallax values determined for the approximated straight line for the previous frame as the given frequency threshold, and to determine the road face candidate points using the determined frequency threshold.