An apparatus for measuring the elevation of a three-dimensional foreground subject which comprises the steps of determining the interrelationship of the first and second images of the three-dimensional foreground subject photographed at two different points to find minute mutually corresponding areas in two images; correcting the first photographed image according to the displacement of the corresponding areas from each other; again determining the interrelationship of the corrected first pseudo-image and the noncorrected second image; correcting the second image by said interrelationship to provide a corrected second pseudo-image; determining the interrelationship of said corrected second pseudo-image and the original second image; repeating the above-mentioned operation; when the determined displacements of the first and second images fall to below a certain value, calculating an algebraic sum of all the determined displacements of said first and second images; and finally measuring the elevation of a three-dimensional foreground subject from the calculated algebraic sum, a distance between the aforesaid two different points of photographing and the already measured height of said two points.