A photoelectric conversion device comprising: a first signal transfer unit group having a plurality of signal transfer units which transfer digital signals to a first common output line from a first holding circuit group; and a second signal transfer unit group having a plurality of signal transfer units which transfer digital signals to a second common output line from a second holding circuit group, wherein each of the plurality of signal transfer units is capable of transiting to a second state in which current consumption is less than current consumption in a first state, and, in a predetermined period, a number of the signal transfer units in the second state increases in the first signal transfer unit group and a number of the signal transfer units in the second state decreases in the second signal transfer unit group.