PURPOSE: To simplify the structure and the operation, and to increase the operating speed by separating a plurality of documents into two groups based on various characteristics to separate the documents in one group from the documents in the other group.

CONSTITUTION: Sheets on a feed table 16 are guided to a path portion of guide plates 58, 60 along guides 34, 35, and wound around a roller 62 through upper and lower track belts 66, 70, and reach the position where the belts 66, 70 are diverted. In addition, the sheets are guided to a movable device 78 which is supported movably between an operative position and an inoperative position at which a diverter is accessible. When the movable device 78 is at the position of the solid line, upper pinch rollers 80, 82 and lower pinch rollers 84, 86 form a nip between themselves and the belt 66 and the belt 70, respectively. A sensor 236 outputs the signal, a gate roller 90 is alternately turned in one direction and the other direction in response to the signal, and the sheets are guided to the upper or lower guide surfaces 96, 102, respectively through the upper or lower nip.