To carry out sort processing to a large number of orders.

Sheet bundles 30 are successively sent out to a receiving position and sorted into each tray 44 of a first sort conveyer 23a. When ten sheet bundles 30 by ten orders are sorted and the first sort conveyer 23a becomes full, an arm 48 is rotated by driving of a motor 50, and a second sort conveyer 23b is set at a supplying position P1. The sheet bundle 30 by an eleventh order is sorted to the tray 44 in the second sort conveyer 23b, and then, the sheet bundles 30 are sorted to the tray 44 until the second sort conveyer 23b becomes full. At the supplying position P1, a third sort conveyer 23c, a forth sort conveyer 23d are set after the second sort conveyer 23b. Sort processing is carried out until each of the sort conveyers 23c, 23d become full.