An automatic paper feeder including an upper light source comprises of a paper tray for holding a plurality of scanning documents, a base frame for mounting on the scanning platform of a scanner, a channel for guiding the scanning document to move along a desired direction and path, an upper light source, a transmission unit for picking up and moving the scanning document, a control unit for controlling the transmission unit and the upper light source, and a cable for wiring the automatic paper feeder to the scanner. The paper feeder enables the scanner to perform paper-feeding type scanning at high scanning efficiency. Beside providing automatic single page feeding, the automatic paper feeder also able to perform transparency scanning through its upper light source. The scanner equips with this automatic paper feeder thus able to perform dual function of reflective type and transparency scanning.