An imaging device includes a plurality of pixels two-dimensionally disposed. At least part of the plurality of pixels includes a first photoelectric conversion unit and a second photoelectric conversion unit provided in a semiconductor substrate and each including a first semiconductor region of a first conductivity type for accumulating a signal charge, a first isolation region provided in the semiconductor substrate between the first photoelectric conversion unit and the second photoelectric conversion unit and including a second semiconductor region forming a first potential barrier for the signal charge in the first semiconductor region, and a second isolation region provided in the semiconductor substrate between the first photoelectric conversion unit and the second photoelectric conversion units and including a trench isolation forming a second potential barrier higher than the first potential barrier for the signal charge in the first semiconductor region.