A guide path branched downward from a conveyance path for guiding a sheet having a toner image fixed thereon to a sheet discharge tray, a switchback path, and a inversed discharge path guide the sheet once, and then guide the sheet to the sheet discharge tray with its front and back surfaces and its leading and trailing edges in a sheet conveyance direction reversed. A fan supplies air between a sheet discharged by a sheet discharge roller and a sheet already discharged onto the sheet discharge tray from a supply opening provided below the sheet discharge roller. A control portion for controlling a blowing operation of the fan selectively operates the fan when discharging the sheet after passing the sheet through the guide path, the switchback path, and the inversed discharge path.