In a contact type image sensor having a sensor array mounting photosensors, a focussing unit for focussing light from an original upon the photosensors, and a frame for holding in position the sensor-array and focussing unit, the focussing unit abuts on the sensor array. In a contact type image sensor having a sensor array having a plurality of face-down sensor chips with a plurality of pixels mounted on a transparent substrate in line, a rod lens array for focussing light from an original, a light source for illuminating the original, and a frame for holding in position the sensor array, rod lens array, the transparent substrate is covered with a light shielding layer in an area other than an area on which the pixels of the sensor chips are mounted and an area corresponding to a focussing area of the rod lens array.