A document conveying apparatus that includes: a paper-supply tray on which documents are stacked; a discharge tray provided below the paper-supply tray; a feeding roller that feeds out the documents one sheet at a time from the paper-supply tray; a conveying mechanism that conveys the fed documents along a conveying path that passes by a reading position; a discharge mechanism that conveys the documents along a discharge path connected to the conveying path and discharges the documents to the discharge tray from a discharge port provided at an end portion on a downstream side in a conveying direction of the discharge path; a conveying roller pair provided at an end portion on an upstream side in the conveying direction of the discharge path; a swing mechanism that swings the discharge mechanism centered around a drive shaft of the conveying roller pair; a raising/lowering mechanism that raises or lowers the paper-supply tray so that the upper surface of the documents stacked on the paper-supply tray is pressed against the feeding roller; an upper surface height measuring unit that measures the height of the upper surface of the documents stacked on the discharge tray; and a control unit that, 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 a difference between the discharge port and the upper surface of the documents stacked on the discharge tray are within a specified range, wherein the raising/lowering mechanism and the swing mechanism are independently formed, and the control unit stores an LUT (Look-up table) where the drive amount of the swing mechanism and the drive amount of the raising/lowering mechanism are associated with each other. a paper-supply tray on which documents are stacked; a discharge tray provided below the paper-supply tray; a feeding roller that feeds out the documents one sheet at a time from the paper-supply tray; a conveying mechanism that conveys the fed documents along a conveying path that passes by a reading position; a discharge mechanism that conveys the documents along a discharge path connected to the conveying path and discharges the documents to the discharge tray from a discharge port provided at an end portion on a downstream side in a conveying direction of the discharge path; a conveying roller pair provided at an end portion on an upstream side in the conveying direction of the discharge path; a swing mechanism that swings the discharge mechanism centered around a drive shaft of the conveying roller pair; a raising/lowering mechanism that raises or lowers the paper-supply tray so that the upper surface of the documents stacked on the paper-supply tray is pressed against the feeding roller; an upper surface height measuring unit that measures the height of the upper surface of the documents stacked on the discharge tray; and a control unit that, 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 a difference between the discharge port and the upper surface of the documents stacked on the discharge tray are within a specified range, wherein the raising/lowering mechanism and the swing mechanism are independently formed, and the control unit stores an LUT (Look-up table) where the drive amount of the swing mechanism and the drive amount of the raising/lowering mechanism are associated with each other.