To provide a technical means that closely contacts a pressing plate made of a hard solid board onto a transparent original platen with respect to a structure especially proper to a flat bed type original reader incorporating a light source lamp to an original cover and can correct an offset of the optical axis of the light source lamp from a read line so as to attain sharper and more uniform reading of an original.

Interposing a cushion spring made of a spring plate between a hinge used to pivotally mount an original cover and a reader main body or freely movably mounting an original pressing board to a cover board closely contacts the original placing board made of a solid board to the transparent original platen at a main body side. Through the structure above, fitting a claw provided to both ends of a lamp unit guide guiding a lamp unit incorporated in the original cover to both ends of a read unit guide at the main body side can prevent an offset between the read unit and the original cover side lamp unit.