An image forming apparatus having a feed unit (55), a door (60), an in-body sheet feed section and a disposable unit (30). The feed unit (55) has a component of a sheet path for single-side printing and a component of a sheet path for double-side printing. The door (60) has a component of the sheet path for double-side pointing. The in-body sheet feed section has a component of the sheet path for single-side printing, and the disposable unit (30) includes a part of the in-body sheet feed section. The feed unit (55) and the door (60) are capable of pivoting on respective pivot shafts (61; 56). When the door (60) is closed, the door (60), the feed unit (55) and the in-body sheet feed section form the sheet path for single-side printing and the sheet path for double-side printing. When the door (60) is open, the disposable unit (30) is attachable to and detachable from the body (1) of the image forming apparatus through the open door (60), and in accordance with the pivoting state of the door (60) and the pivoting state of the feed unit (55), the door (60) and the feed unit (55) become a first state wherein the sheet path for single-side printing and the sheet path for double-side printing are open and become a second state wherein the feed unit (55) retreats from the locus of the disposable unit (30) to and from the body (1) of the image forming apparatus.