An image forming apparatus includes: a process unit having a photosensitive body extending in a first direction; a first roller disposed on one side in a second direction of the process unit, which is substantially perpendicular to a vertical direction and the first direction; an exposure unit; a fixing unit disposed on the other side in the second direction of the process unit; and a second roller disposed on an upper side of the fixing unit and on the other side in the second direction of the first roller and configured to transport the recording medium passed through the fixing unit to an outside of a casing. The casing includes a guide portion configured to guide the process unit into the casing, and the exposure unit is disposed on the one side in the second direction of the process unit and the guide portion.