An image forming apparatus includes an image carrying member; an image forming section to form a toner image on the image carrying member; a transferring section to transfer the toner image formed on the image carrying member to a sheet; a fixing section to fix the toner image onto the sheet; a sheet feeding section to feed a sheet to the transferring section; a sheet tray to store sheets to be fed by the sheet feeding section; a dehumidifying heater arranged to the sheet tray and to perform dehumidification for sheets; a waste toner box arranged to adjoin the sheet tray and to accommodate waste toner; and a partition member arranged between the sheet tray and the waste toner box and between the dehumidifying heater and the waste toner box.