To decrease the total number of paper sheets which cannot heretofore be put into any of sorting boxes by collecting the paper sheets which are the paper sheets continued with each other, the paper sheets rejected by the fullness of the destination sorting boxes, the paper sheets rejected by the stoppage of transporting paths having the destination sorting boxes, or the like, retransporting these paper sheets without the aid of manpower and stacking the stackable paper sheets into the sorting boxes.

The resupplying boxes 24, which can collect the paper sheets failing to be put into any of the sorting boxes 12 and can feed the paper sheets again into the transporting paths 47, are prepared. The paper sheets collected into the resupplying boxes 24 are transported again and the paper sheets stackable into the sorting boxes 12 are stacked into the sorting boxes 12. Only the paper sheets which cannot be put into any of the sorting boxes are put into reject boxes 23.