PURPOSE: To provide a scanning device capable of preventing the narrowing of the effective scanning region of a scanner caused by the interference of a scanner end part to a pulley and further easily joining a toothed belt and the pulley in the structure for joining the toothed belt of the scanning device and both end parts of the scanner.

CONSTITUTION: In the scanning device driving both end parts of an optical scanning member 2 by two sets of the toothed belts 1 and the pulleys 3a and 3b, the joining part 4 of the toothed belt 1 for driving an optical scanning member 2 and the member 2 is positioned in a side having no tooth of the toothed belt 1 and the effective scanning range 11 of the optical scanning member 2 is almost equal to inter-axes distance between two pulleys 3a and 3b.