To easily apply setting operation of a book original to an original platen by the operator.

The original platen is provided with an original platen moving restriction 300 that restricts the movement of a 2nd original platen 102 in a separating direction in the case that the operator moves the 2nd original platen 102 in a direction approaching a 1st original platen 101. The original platen moving restriction 300 is made up of a ratchet mechanism consisting of a ratchet 301 having a sawtooth gear train and a lock claw meshing with the teeth of the ratchet 301, and in the original platen 100, the ratchet 301 is provided to a front side face of an original platen support member 107 and the lock claw is placed in the inside of the front side face of the 2nd original platen 102.