A medium discharging device includes a side cursor, a moving unit, a discharge unit, and a side guide. The side cursor is provided in a processing tray and is provided movable in an intersecting direction intersecting a discharging direction of the medium, aligns an end portion of a media bundle in the intersecting direction, and guides the media bundle in the discharging direction when the media bundle is discharged. The moving unit moves the side cursor in the intersecting direction. The discharge unit discharges the media bundle from the processing tray to the discharge tray where the media bundle is placed. When the media bundle is discharged, the side guide is disposed alongside the side cursor in the discharging direction and restricts movement of the media bundle in the intersecting direction, which is discharged by the discharger.