A document feeder includes a document placing tray on which a document is placed; a document discharging tray on which a document discharged from a document discharging port in a discharging direction is stacked; and a light source that radiates light to the document discharging tray. The document discharging tray is disposed below the document placing tray. The document discharging tray has a protruding portion protruding upward from the surrounding area. The light source is disposed within a region having a width that is the same as a document having a maximum size in the width direction.