An optical image scanning device includes a casing having a document supporting plate and a top cover. The top cover has an underside surface coated with a fluorescent material thereon. An optic module includes a light source for projecting an exciting light onto the fluorescent layer whereby the fluorescent material is excited by the exciting light to emit a scanning light. The scanning light transmits through a light-transmittable document and projects an image of the document onto reflective mirrors for guiding the scanning light through a focusing lens. The focusing lens focuses the light onto a image sensing device. A reflective type light source is selectively arranged in the optic module for selectively projecting a light onto a document formed on a non-transmissive medium that is positioned on the document supporting plate.