A photoelectric transducer has an optical waveguide and a photoelectric transducer element array of photoelectric transducer elements optically coupled to the optical waveguide. The photoelectric transducer element array has a common conductive layer, and the photoelectric transducer elements are mounted on the common conductive layer in alignment with entrance or exit ends of the optical waveguide. The photoelectric transducer elements having respective first poles, and the photoelectric transducer element array has a second pole disposed in opposite relation to the first poles and connected as a reference potential setting electrode through the common conductive layer to at least two of the photoelectric transducer elements.