A received document sorting control method for an image processing device that has a facsimile communication unit for communications via Internet, and receives documents by means of the facsimile communication unit, comprising: previously setting prescribed condition information for judging whether or not a received document is subject to automatic sorting, and for judging a prescribed sorting method in a case that automatic sorting is to be implemented; and checking contents of transmission identification information transmitted by a sender on the basis of the prescribed condition information, and controlling automatic sorting processing for a document received in a communication, in accordance with the corresponding prescribed sorting method, if the document received in the communication is judged to be subject to the automatic sorting.