Provided is a document conveying apparatus that properly discharges documents regardless of the amount of documents stacked on a discharge tray without complicated construction of a transmission mechanism for transmitting a driving force to conveying rollers. A conveying roller pair (97) is provided at an end portion on an upstream side. A swing mechanism (37) swings a discharge mechanism (36) centered around a drive shaft of the conveying roller pair. An upper surface height measuring unit (19) measures the height of the upper surface of documents stacked on the discharge tray (43). A control unit (10), by causing the swing mechanism to swing the discharge mechanism according to the height measured by the upper surface height measuring unit, performs control so that the difference between a discharge port (70) and the upper surface of the documents stacked on the discharge tray is within a specified range.