Provided is a photoelectric conversion device including: a plurality of pixel circuits each including a photoelectric conversion unit configured to generate charges by photoelectric conversion and a transistor configured to transfer the charges from the photoelectric conversion unit; and a plurality of exposure control circuits each including a capacitor configured to hold a signal corresponding to an exposure period in the photoelectric conversion unit and a comparator circuit configured to compare a potential of a first terminal of two terminals of the capacitor with a threshold potential. Each of the plurality of exposure control circuits controls an exposure period of the photoelectric conversion unit by outputting a signal based on a comparison result caused by the comparator circuit to a control terminal of the transistor and driving the transistor.