1. A three-dimensional feature data generating device that generates three-dimensional data of a feature, from stereo images, and the three-dimensional feature data generating device includes: a stereo disparity calculating unit that calculates a predicted value of stereo disparities between pixels on the stereo images relating to height information of a terrain and features; a line extracting unit that extracts lines from an image, which are characteristic lines representing an internal structure of a rooftop of each feature, contour lines representing an external shape of each feature, and characteristic lines of each non-feature object; a line classification unit that classifies the lines extracted by the line extracting unit into three classes according to their respective meaning in the real world, including any of internal rooftop lines of features, external contour lines of features, and contour lines of shadow areas; a meaningless line eliminating unit that eliminates the lines that do not exist in the real world but are generated due to an influence of shadow or image noise; a line pair determining unit that determines, for each line in one image of a stereo image pair, its corresponding line in another image of the stereo image pair, based on disparity information from the stereo disparity calculating unit, color and texture distribution patterns of a neighboring region around each line, and a line classification result; a stereo disparity correcting unit that calculates a more precise value of disparities between pixels on the stereo images based on a correspondence relationship of each line pair obtained by the line pair determining unit, to correct the predicted value of stereo disparities between pixels on the stereo images obtained by the stereo disparity calculating unit; a line pair clustering unit that firstly selects, among the line pairs obtained by the line pair determining unit, only the line pairs related to features including a residential building, an architectural structure and the like, and then utilizes both the disparity information of each line pair and a geometrical relationship of several line pairs to finally cluster the line pairs belonging to the same feature as one line pair cluster; a plane extracting unit that extracts basic planes configuring a feature based on the geometrical relationship and disparity information of the line pairs in each line pair cluster obtained by the line pair clustering unit; and a plane combining unit that calculates a three-dimensional relative location relationship between planes of each feature extracted by the plane extracting unit to generate a three-dimensional model representing the whole structure of each feature.