1. An image reading apparatus for reading an original image, comprising: an imaging device; optical means located for exposing said imaging device and capable of moving in two directions perpendicular to each other; a reading operation control unit for controlling a first reading operation in which whole information of said original image is read, and a second reading operation in which division image information in division areas of said original image is read; resolution setting means for setting a resolution in said second reading operation; a data processing unit for connecting a plurality of adjacent division image information sets which are read in a plural number of times in said second reading operation, so as to generate front view image information of said original image; said data processing unit including edge information detection means for detection edge information of images of a whole image and division images, said whole image being detected in said first reading operation, said division images being read in said second reading operation; positioning means for positioning said division images in said whole image so that each of said division images is coarsely positioned on the basis of edge correlation between edge information of said whole image and edge information of said division images; and an image synthesis unit for synthesizing and registering said division images precisely on the basis of said edge information of adjacent division images positioned by said positioning means.