An image sensor includes a charge accumulation region of a first conductivity type, an isolating semiconductor region formed from an impurity semiconductor region of a second conductivity type, a channel stop region formed from an impurity semiconductor region of the second conductivity type which is located on the isolating semiconductor region, and an insulator arranged on the channel stop region. The insulator includes a first insulating portion arranged above the isolating semiconductor region via the channel stop region, a second insulating portion arranged adjacent to an outside of the first insulating portion, wherein thickness of the second insulating potion decreases with an increase in distance from the first insulating portion, and a third insulating portion formed on the first insulating portion, wherein the third insulating portion has upper and side faces connecting the upper face to an upper face of the second insulating portion.