An image forming apparatus (1) includes a discharge port (25), a sheet stacking plate (41), a pair of cursors (43), a cursor driver (95), a pair of blowers (83) and a controller (37). Through the discharge port (25), a sheet formed an image is discharged. On the sheet stacking plate (41), the sheet discharged through the discharge port (25) is stacked. The pair of cursors (43) is supported on the sheet stacking plate (41) in a slidable manner in width directions perpendicular to a discharge direction of the sheet and comes into contact with both side edges of the sheet. The cursor driver (95) drives the pair of cursors (43). The pair of blowers (83) is provided in the pair of cursors (43) so as to blow air to both corners on an upstream side in the discharge direction of the sheet which is discharged through the discharge port (25), from above. The controller (37) controls the cursor driver (95) and the pair of blowers (83).