A photoelectric conversion device includes photoelectric conversion elements and element isolation regions, both of which are arranged on a semiconductor substrate. The photoelectric conversion device further includes a plurality of interlayer insulation layers including a first interlayer insulation layer arranged nearest to the semiconductor substrate, and a second interlayer insulation layer arranged to cover the first interlayer insulation layer. Gaps extending from at least the second interlayer insulation layer to the first interlayer insulation layer are arranged in first and second interlayer insulation layer regions corresponding to the element isolation regions.