1. A specified image position estimating apparatus comprising: position detection point detecting unit for, in a state where three or more position detection marks, each of which is formed such that two or more straight lines intersect with each other or come into contact with each other at one position detection point, are affixed to an original image, detecting said position detection point of each of said position detection marks on said original image; and specified image position estimating unit for estimating a position of a specified image in said original image on the basis of said position detection point detected by said position detection point detecting unit.