To provide a sheet stacking device capable of improving an aligning property of stacked sheets on a stacking tray by surely stopping a sheet at a predetermined position with a simple constitution, or stopping the sheet at a predetermined position while minimizing an abutting amount (an overrun amount) to a stopper member.

This device includes detection means for detecting a moving amount of sheets conveyed on a stacking tray, drive means for driving and stopping conveying means based on detection results of the detection means, and movement means for moving the conveying means and the detection means according to size information. The device is also provided with aligning means for stopping the sheets conveyed on the stacking tray, and movement means for moving the conveying means, the detection means and the aligning means according to size information.