To attain a long service life of a sensor and to improve a read performance by arranging a lighting means to casing frame other than a casing frame of a close contact sensor main body and providing a glass plate through which a light from the lighting means is emitted to an original.

This sensor is configured such that a light source space through which a light of a tube light source 6 is emitted to a read light position A and a read space used for forming an image read at the read position A by a photoelectric conversion means 3 are separated into a casing frame 7 side and a casing frame 5 side, with an optical guide glass plate 8 inbetween. Thus, the thermal expansion of a SELFOC lens array 2, due to heat generated in a light source 6, is suppressed and the service life of the photoelectric conversion means 3 and a mount board 4 is attained. The light of a tube light source 6 is emitted to the rear position A with a sufficient illuminance by using a condenser lens in place of the optical guide glass plate 8. Further, light and heat conductive elastic body may be fitted in close contact with a rear side tube wall of the tube light source 6 and the casing frame 7, so as to dissipate the heat of the tube light source 6 from the casing frame 7 through the elastic body.