In an image sensor including a first column readout line and a second column readout line provided to each pixel column, a plurality of pixel rows are divided into pixel rows of a first group and pixel rows of a second group, pixels of the pixel rows of the first group output signals to the first column readout line, and pixels of the pixel rows of the second group output signals to the second column readout line. A shortest distance between a conversion region of a first pixel of a pixel row of the first group and the first column readout line to which a signal from the first pixel is output is not more than a shortest distance between the conversion region of the first pixel and the second column readout line to which the signals from the pixels belonging to the pixel rows of the second group are output.