Original scanning apparatus and control method thereof

An original scanning apparatus that scans an original placed on an original placing plane line by line by moving a scanning unit comprising a plurality of light-receiving elements that are arranged in a prescribed direction in a direction perpendicular to the prescribed direction, the apparatus comprising:

• a pattern unit that is provided in a vicinity of a side of the original placing plane extending along a moving direction of the scanning unit;
• a control unit configured to calculate drive information in the moving direction per line-scanning cycle of the scanning unit based on a result of scanning the pattern unit by using a plurality of light-receiving elements that are provided at a position corresponding to the pattern unit from among the plurality of light-receiving elements;
• and
• a driving circuit configured to feed back the drive information calculated by the control unit so as to control the scanning unit to thereby drive the scanning unit in the moving direction,
• wherein, in the pattern unit, lines each having a slant with respect to the prescribed direction are formed at a regular interval in the moving direction of the scanning unit.