A photoelectric conversion apparatus includes a pixel array having pixels arranged to form rows and columns and column signal lines configured to output noise signals and optical signals of the pixels, a driver configured to drive the pixels so that the optical signal is output following the noise signal from each pixel, A/D converters configured to perform A/D conversion to convert the noise signals output to the column signal lines into noise data and to subsequently perform A/D conversion to covert the optical signals output to the column signal lines into optical data, a data hold circuit, and a transmitter configured to transmit the noise data converted by the A/D converters to the data hold circuit and to subsequently transmit the optical data converted by the A/D converters to the data hold circuit.