A photoelectric conversion device includes analog signal output units including pixels and configured to output analog signals based on pixels, and signal processing units. Each of the signal processing units is provided correspondingly to one of the analog signal output units and including a gain application unit configured to apply a gain to an analog signal by using only passive elements and an AD conversion unit. In the gain application unit, a portion that contributes to application of a gain to the analog signal is constituted only of passive elements. The gain application unit selectively outputs a first amplified signal obtained by applying a first gain to the analog signal or a second amplified signal obtained by applying a second gain to the analog signal smaller than the first gain. The AD conversion unit converts, from analog to digital, the first or second amplified signal.