1. A measuring apparatus for measuring a distance between two points of a start point and an end point, using a plurality of images photographed while shifting a photographing range of a measurement target, comprising: coordinate calculation means for calculating coordinates of the start point in an image in which the start point is set, and coordinates of the end point in an image in which the end point is set, and storing the calculated coordinates in a storage unit; representative point setting means for setting a representative point in the image in which the start point is set, at the position of coordinates that are different from those of the start point, storing the coordinates of the representative point and characteristic quantity of a neighborhood image, searching the representative point that is set most recently in each image after the image in which the start point is set to the image in which the end point is set, setting a new representative point at the position of coordinates that are different from the coordinates of the detected representative point, and storing the coordinates of the new representative point and characteristic quantity of the neighborhood image in the storage unit; representative point searching means for searching the representative point in each image from the image in which the start point is set to the image in which the end point is set, based on the characteristic quantity of the neighborhood image of the representative point that is set most recently, and storing the coordinates of the detected representative point in the storage unit; vector calculation means for calculating a vector between two points in a same image respectively, for the start point and the representative point in the image in which the start point is set, for the representative points which are set at different positions in a same image, and for the representative point and the end point in the image in which the end point is set, using the stored coordinates of the start point, the representative points and the end point; and distance calculation means for calculating a distance between the start point and the end point based on the vector from the start point to the end point, that is determined by adding all the calculated vectors.