The photoelectric conversion device includes a pixel unit configured to output first and second signals from columns of first and second regions, and a processing circuit including a first processing circuit including first and third memories, a second processing circuit including second and fourth memories, and a data exchange circuit. The first memory stores the first and second signals output from the first region, and the second memory stores the first and second signals output from the second region. The data exchange circuit stores the first signals read out from the first and second memories in the third memory, and stores the second signals read out from the first and second memories in the fourth memory. The processing circuit outputs the first signals stored in the third memory from the first processing circuit, and outputs the second signals stored in the fourth memory from the second processing circuit.