A photoelectric conversion device may include a plurality of A/D converters each of which receives a pixel signal from a pixel array that includes pixels arranged two-dimensionally. Each of the pixels may have a photoelectric conversion element. The pixel array may output the pixel signal in accordance with an incident light amount to the photoelectric conversion element. The plurality of A/D converters may convert the pixel signal to a digital value based on a reference voltage. The plurality of A/D converters may output the digital value. A reference voltage wire, which supplies the reference voltage to each of the plurality of A/D converters, may be branched into a plurality of branched reference voltage wires each of which is corresponding to one of the plurality of A/D converters. Each of the plurality of branched reference voltage wires may be connected only to constituent components in a corresponding A/D converter.