1. An image processing apparatus for identifying an object in a document image, which has been scanned by a scanning unit, as well as a mark that has been added to the document, and storing image data of the object in a storage unit upon classifying the image data in accordance with the mark identified, said apparatus comprising: an extraction unit adapted to extract information representing a region position of the object and information representing a region position of the mark as an object list and mark list, respectively, from the document image that has been scanned by the scanning unit; and a search unit adapted to search for information representing the region position of a mark in the mark list for which the distance is the shortest with respect to information representing a region position of each object in the object list.