1. An image analysis system which captures image data of an arbitrary pair of a first image and a second image among two or more images obtained by color-photographing a single photographing object from different photographing positions into an image analysis computer for analysis, wherein the image analysis computer comprises: corresponding point extraction means for assigning a weighing factor to a pixel information value based on the contrast size of the pixel information value describing characteristics of a pixel in each of a first local area set around an arbitrary reference point in the first image and second local areas which are set to the same size as the first local area inside the second image and at which scanning is performed on the second image, calculating the similarity between the first local area and the second local areas, and extracting a corresponding point which corresponds to the reference point from a second local area having the highest similarity; and depth information calculating means for calculating depth information of the photographing object based on coordinates between the reference point and the corresponding point.