An image forming apparatus includes a main body and a processing apparatus. The processing apparatus includes a first processing unit and a second processing unit. The main body has a manual-feed tray at one lateral face. The first processing unit and the second processing unit are stacked in the vertical direction on the same lateral face side of the main body as the manual-feed tray provided. The second processing unit is slidable in a toward-away direction between a connecting position and a separate position, and has a hollow to insert the manual-feed tray therein at the connecting position.