An image forming apparatus capable of reducing a space required to install a transfer unit to achieve a compact body size. The image forming apparatus can include a body, a frame installed in the body, a transfer unit installed inside the frame, and a waste toner recovery device to recover waste toner collected from the transfer unit. The waste toner recovery device can include a first delivery unit to deliver the waste toner in a first direction, and a second delivery unit to deliver the waste toner, delivered from the first delivery unit, in a second direction. The second delivery unit can be movably installed to the frame and can be coupled to or detached from the first delivery unit via movement thereof.