A banknote storing system for providing an economical and space-efficient storage of banknotes of various sizes in a removable banknote storage unit is provided. A banknote transporting unit can move a banknote with a movable elongated belt unit to a position over a gap position on the removable banknote storage unit. The slider unit in the banknote storage unit can move relative to a movable elongated bank unit for forcing the banknote unit into a storage area. The slider unit can form a pair of U-shaped channels that are positioned above the gap for laterally receiving the banknote when transported by the movable elongated belt unit.