A photoelectric conversion apparatus according to an exemplary embodiment includes a plurality of pixels each including a photoelectric conversion unit, a transistor configured to process a signal charge generated in the photoelectric conversion unit, and an analog-to-digital conversion circuit. The apparatus further includes a first semiconductor substrate on which the photoelectric conversion units and the transistors of the plurality of pixels are two-dimensionally arranged, a second semiconductor substrate on which a plurality of circuit blocks is two-dimensionally arranged, a bonding portion configured to electrically connect the first semiconductor substrate and the second semiconductor substrate, and a wiring arranged between the first semiconductor substrate and the bonding portion. The wiring is connected to the transistors of the plurality of pixels and configured to supply a control signal to the transistors of the plurality of pixels.