A copying machine is disclosed which is capable of copying an original document having a page number by preliminarily erasing or correcting the page number portion of the image and by changing the order of the output images according to their respective page numbers or by changing the path for delivering the sheet of paper to be copied. A document page image read-in by a charge coupled device sensor is converted into digital signals which are corrected for shading and then binarized and stored in an image memory. This image data is transferred to a working memory wherein the page number shown on the document is read by a page number recognizing unit. The control unit checks the page number and allocates a binding margin on a suitable portion of the document's image. On the basis of the recognition of the page number on the document's image, it also decides to copy the document on one side of the sheet of paper and to deliver it out, or to copy the next document onto the other side of the sheet of paper.