To smoothly perform guiding action for the movement of a scanner by constituting a guide member for moving the scanner in a read frame as a member which is not influenced by the distortion or the like of the read frame.

In reading the image of an original set on a platen 24 by moving the scanner 10, the scanner 10 is guided in a state where a guide rail 27 projecting from the bottom plate of the frame and constituted so that its top becomes circular-arc shape is inserted in a groove-shaped part to be guided 19 provided to the scanner 10. The scanner 10 is guided by a slide guide 26 whose surface friction coefficient is set to be small at the other rear side projecting part 16 of the scanner 10, and it slides by frictional force whose value is small with respect to the projecting part 16 by applying force to pull down a front side projecting part 17 by a driving belt 18.