An image forming apparatus capable of effectively cooling down a sheet having been subjected to fixing processing while preventing an apparatus from becoming larger in size and a sheet conveyance failure from occurring is provided. The image forming apparatus (10) includes a sheet conveyance path (16), a fixing device (22), a conveyance roller (26), an upper sheet guide (60), a lower sheet guide (62), and a cooling fan (40). The conveyance roller (26) is disposed downstream of a heat-treatment portion in the sheet conveyance path and configured so as to convey a sheet passing the heat-treatment portion to the paper output tray. At a position corresponding to the position of the conveyance rollers (26), the upper sheet guide (60) is provided with a ventilation portion (604) configured so as to make the cooling air from the cooling device (40) pass through. At a position opposed to the ventilation portion (604) of the upper sheet guide (60), the lower sheet guide (62) is provided with a ventilation portion (624) configured so as to make the cooling air from the cooling device (40) pass through.