An automatic document feeder is formed of a transfer device having a transfer belt situated above a platen to transfer a sheet on the platen, and a belt motor for actuating the transfer belt, a sheet detecting device situated near the transfer belt for detecting the sheet, and a feeding device located near the transfer belt at a side of the sheet detecting device. The feeding device feeds the sheet between the transfer belt and the platen. A controlling device is electrically connected to the sheet detecting device and the belt motor. The controlling device, while the belt motor for transferring the sheet on the platen is actuating, outputs a stop signal to stop the belt motor when a predetermined time has passed after the sheet detecting device detects the sheet so that the sheet is placed on a predetermined position on the platen. The feeder further includes a compensating device connected to the controlling device. The compensating device assumes an amount of overrun of the belt motor from a time that the belt motor receives the stop signal to a time that the belt motor actually stops, and compensates a time that the stop signal is outputted from the controlling device based on the overrun amount. Thus, the sheet is stopped at the predetermined position.