Post-processing apparatus

A post-processing apparatus includes a conveyance unit, a discharge port, a tray, an elevation unit, a detection unit, and a control unit. The conveyance unit conveys a print medium supplied from an image forming apparatus. The discharge port discharges the print medium conveyed by the conveyance unit. The tray is stacked with the print medium discharged from the discharge port and can be raised and lowered in a vertical direction. The elevation unit raises and lower the tray in the vertical direction. The detection unit detects a top surface of an uppermost print medium of one or more sheets of print media stacked on the tray. The control unit controls the conveyance unit and the elevation unit and hold a relative position of the top surface with respect to the discharge port if the print medium is discharged from the discharge port at a first position. The control unit causes the conveyance unit to convey the print medium at a first speed if a discharge time from a first timing indicating the timing relating to discharge of the print medium from the discharge port to a second timing indicating the timing when the print medium is detected by the detection unit is a first time and causes the conveyance unit to convey the print medium at a second speed different from the first speed if the discharge time is a second time.