A document reading apparatus including: a first scanning section that moves in a scanning direction along a document surface, for supporting a first mirror to reflect an image of a document in a direction parallel to the scanning direction; an intermediate scanning section that moves synchronous with the first scanning section, for supporting an intermediate mirror to reflect the image of the document reflected by the first mirror in a direction opposite from an incident direction of the image; a reading section including an imaging sensor for reading the image of a scanned document and a focusing lens for focusing the image of the document reflected by the intermediate mirror on the imaging sensor; a driving wire for pulling the first scanning section in the scanning direction; a supporting pulley for supporting the driving wire at a starting side for scanning or at an ending side for scanning; a position adjustment section capable of adjusting a position of the supporting pulley in its axial direction; a control section for performing such control that the image for adjustment is read by the reading section when the first scanning section is located at a first position and at a second position in the scanning direction, and an adjustment amount of the position adjustment section is calculated based on a readout result of the image; and an output section for outputting the calculated adjustment amount.