A photoelectric conversion array is comprised of a longitudinal semiconductor substrate formed with a plurality of doped regions electrically isolated from one another and equidistantly aligned in the longitudinal direction of the substrate. Each doped region is comprised of a first region containing therein base, collector and emitter regions arranged to constitute a bipolar phototransistor operative in response to irradiation of incident light onto the base region to induce a photoelectric current between the collector and emitter regions, and a second region disposed adjacent to and laterally of the first region and containing therein a drain region, a source region, a channel region between the drain and source regions and a gate region disposed on the channel region to constitute a MOS switching transistor electrically connected in series to the bipolar phototransistor and selectively operative in response to a control voltage applied to the gate region to enable the induced photoelectric current to flow through the channel region to thereby drive the corresponding bipolar phototransistor.