A recording material stacking apparatus equipped with a plurality of discharge ports and a plurality of stacking trays can be set to normal mode and large capacity stacking mode each having a different maximum loading capacity. A stacking tray on the upper side has a plurality of lower limit positions and uses a lower limit position located on the upper side when normal mode is selected. On the other hand, it uses a lower limit position located on the lower side when the large capacity stacking mode is selected. The lower limit position located below a stacking tray on the upper side when this large capacity stacking mode is selected exists at a position in which it blocks a lower discharge port of sheets. Selection of the large capacity stacking mode and normal mode is executed according to a result of computation from data input through an input portion.