A document transporting device (30) serves as a platen cover to expose and cover platens (21A,21B). A document holder (5) is mounted on a predetermined mounting portion of the device (30). A lateral end of the document holder (5) is withdrawn from a predetermined position where the end is located, so that a document transport path (R) is exposed through an area in which the document holder (5) has been withdrawn. The document transport path (R) is exposed to the left or the right with respect to the front of the device (30).