A photoelectric conversion device comprises a plurality of pixels, a driving supplemental element, a signal line to which the plurality of pixels and the driving supplemental element are connected, a driving unit which drives the plurality of pixels and the driving supplemental element, and an output circuit which processes a signal output to the signal line from a readout pixel selected by the driving unit and outputs the processed signal, each of the plurality of pixels including a first charge-voltage converter, a first reset unit which resets the first charge-voltage converter, and a first output unit which outputs a signal corresponding to a voltage of the first charge-voltage converter, the driving supplemental element including a second charge-voltage converter, a second reset unit which resets the second charge-voltage converter, and a second output unit which outputs a signal corresponding to a voltage of the second charge-voltage converter.