According to one embodiment, a back side illumination type solid-state imaging device includes an imaging area in which a plurality of unit pixels each including a photoelectric conversion section and a signal scan circuit section are arranged on a semiconductor substrate, and a light illumination surface formed on a surface of the semiconductor substrate located opposite a surface of the semiconductor substrate on which the signal scan circuit section is formed, wherein the unit pixel comprises a high-sensitivity pixel and a low-sensitivity pixel with a lower sensitivity than the high-sensitivity pixel. And each of the high-sensitivity pixel and the low-sensitivity element comprises a first pixel separation layer located on the light illumination surface side in the semiconductor substrate to separate the pixels from each other.