An imaging element that has a plurality of pixel blocks arranged side by side in a first direction and a second direction intersecting with the first direction, comprising: a plurality of first pixels that are arranged in a first pixel block among the plurality of pixel blocks, each first pixel having a first photoelectric converting unit configured to convert light incident thereto into a charge, and configured to generate first data based on charge accumulated in the first photoelectric converting unit for a first accumulation period; a plurality of second pixels that are arranged in the first pixel block, each second pixel having a second photoelectric converting unit configured to convert light into a charge, and configured to generate, based on charge accumulated in the second photoelectric converting unit for the first accumulation period, second data used to eliminate dark-current noise of the first photoelectric converting unit included in the first data, the second pixels being randomly arranged in the first pixel block; a plurality of third pixels that are arranged in a second pixel block among the plurality of pixel blocks, each third pixel having a third photoelectric converting unit configured to convert light incident thereto into a charge, and configured to generate third data based on charge accumulated in the third photoelectric converting unit for a second accumulation period that is different from the first accumulation period; and a plurality of fourth pixels that are arranged in the second pixel block, each fourth pixel having a fourth photoelectric converting unit configured to convert light into a charge, and configured to generate, based on charge accumulated in the fourth photoelectric converting unit for the second accumulation period, fourth data used to eliminate dark-current noise of the third photoelectric converting unit included in the third data, the fourth pixels being randomly arranged in the second pixel block, wherein an arrangement pattern of the second pixels in the first pixel block is different from an arrangement pattern of the fourth pixels in the second pixel block, wherein the plurality of the first pixels, the plurality of the second pixels, the plurality of the third pixels, and the plurality of the fourth pixels have color filters, and wherein the plurality of the second pixels and the plurality of the fourth pixels include light blocking layers between the respective color filters and the photoelectric converting units. a plurality of first pixels that are arranged in a first pixel block among the plurality of pixel blocks, each first pixel having a first photoelectric converting unit configured to convert light incident thereto into a charge, and configured to generate first data based on charge accumulated in the first photoelectric converting unit for a first accumulation period; a plurality of second pixels that are arranged in the first pixel block, each second pixel having a second photoelectric converting unit configured to convert light into a charge, and configured to generate, based on charge accumulated in the second photoelectric converting unit for the first accumulation period, second data used to eliminate dark-current noise of the first photoelectric converting unit included in the first data, the second pixels being randomly arranged in the first pixel block; a plurality of third pixels that are arranged in a second pixel block among the plurality of pixel blocks, each third pixel having a third photoelectric converting unit configured to convert light incident thereto into a charge, and configured to generate third data based on charge accumulated in the third photoelectric converting unit for a second accumulation period that is different from the first accumulation period; and a plurality of fourth pixels that are arranged in the second pixel block, each fourth pixel having a fourth photoelectric converting unit configured to convert light into a charge, and configured to generate, based on charge accumulated in the fourth photoelectric converting unit for the second accumulation period, fourth data used to eliminate dark-current noise of the third photoelectric converting unit included in the third data, the fourth pixels being randomly arranged in the second pixel block, wherein an arrangement pattern of the second pixels in the first pixel block is different from an arrangement pattern of the fourth pixels in the second pixel block, wherein the plurality of the first pixels, the plurality of the second pixels, the plurality of the third pixels, and the plurality of the fourth pixels have color filters, and wherein the plurality of the second pixels and the plurality of the fourth pixels include light blocking layers between the respective color filters and the photoelectric converting units.