After accumulating electric charges in pixels in first, second, and third rows, signals are output from the pixels in the first and second rows in a first frame, and thereafter, after accumulating electric charges in the pixels in the first row without accumulating electric charges in the pixels in the second and third rows, signals are output from the pixels in the first and third rows in a second frame following the first frame. Furthermore, the photoelectric conversion units of the pixels in the second and third rows are reset by the resetting units included in the pixels in the second and third rows in the first frame.