An image-forming apparatus comprises a machine body and a paper discharge unit removably attached to the machine body. The machine body defines a face-down discharge tray on top. The paper discharge unit includes a face-up discharge tray and a discharge roller pair. A switch lever is provided in the machine body for selecting between a state in which recording paper is turned over for discharge onto the face-down discharge tray, and a second state in which the recording paper is discharged face up onto the face-up discharge tray.