Abstract: Documents to be imaged which lie one upon another in a prescribed order of page on an automatic document feeding device are automatically fed one by one to a scanning reference position defined in an image scanning position of an image processing device and discharged, after being imaged, to a discharge tray in the same order of page as those initially stacked. The document sent out from the image scanning position to a delivery passage after being imaged is sent back to the document scanning position through a return passage to be turned over. When the document being sent back is introduced into the image scanning position by the longitudinal size of the document, document transporting means is reversed to discharge the document, thereby to shorten the time required to discharge the document from the image scanning position to the discharge tray through a document discharge passage.