A post-processing device includes an intermediate tray on which a medium transported in a transport direction is placed, a discharge port through which the medium post-processed on the intermediate tray is discharged, a discharge tray which is disposed in a gravity direction with respect to the discharge port and on which the medium discharged from the discharge port is placed, and an elevating mechanism which elevates the discharge tray, in which the elevating mechanism can move the discharge tray to a first normal position and a first standby position positioned in a direction opposite to the gravity direction with respect to the first normal position, and moves the discharge tray to the first normal position or the first standby position according to an amount of ink before the medium comes in contact with the discharge tray or the medium previously placed on the discharge tray.