A photoelectric conversion device includes a plurality of pixels arranged in a plurality of columns, a plurality of comparators provided correspondingly to the respective columns, a reference signal generation unit configured to supply a reference signal to the plurality of comparators, a counter configured to generate a count signal that includes a plurality of bits in synchronization with a first clock signal, a synchronization unit configured to synchronize the plurality of bits with a second clock signal to generate a synchronized count signal and to output the generated synchronized count signal, and a plurality of memories provided correspondingly to the respective comparators, the memories each being configured to store the synchronized count signal in response to a change in an output of a corresponding one of the comparators.