PURPOSE: To easily attain attachment and position adjustment of first and second scanners.

CONSTITUTION: The first scanner 1 is attached to a first clamp 7, and simultaneously, plural projecting parts 10 engaged with the tooth part of a first scanner drive timing belt 5 are formed on the first clamp 7. A second clamp 11 is attached to the second scanner 2, and simultaneously, a press-contacting part 14 press-contacting with a second scanner drive timing belt 6 to fix it together with a receiving part 13 is formed on the second clamp 11. On the other hand, Attaching positions to the first scanner drive timing belt 5 of the first clamp 7 and to the second scanner drive timing belt 6 of the first clamp 11, are set in the upper part than a timing pulley on which the first and second scanner drive timing belts 5 and 6 are stretched.