This solid-state image sensor includes an array of photosensitive cells and an array of dispersive elements. The photosensitive cell array is comprised of a plurality of unit blocks 40, each including four photosensitive cells 2a, 2b, 2c and 2d. An optical filter 11a is arranged to cover those photosensitive cells 2a through 2d. A portion of the optical filter 11a that covers the photosensitive cells 2a and 2b is located closer to the imaging area than another portion thereof that covers the photosensitive cells 2c and 2d.