An image forming apparatus includes a discharge tray, a plurality of ribs, a ventilation duct, a ventilation hole, and an air flow generating portion. On the discharge tray, a sheet having been subjected to a fixing process for thermally fixing a toner image on the sheet is discharged. The plurality of ribs are formed on the discharge tray. The ventilation duct is formed on a side of an end among opposite ends of each of the plurality of ribs. The ventilation hole is formed in a partition wall separating the ventilation duct from a sheet mounting area of the discharge tray, and formed in a vicinity of the end of each of the plurality of ribs on the partition wall side. The air flow generating portion is configured to generate, via the ventilation duct, air flow between outside of an apparatus main body and spaces between the ribs.