Abstract: A solid-state image sensor includes a substrate including a photoelectric conversion portion, an insulating layer having an opening, and a member arranged inside the opening. Letting d be a depth of the opening, the opening has, at an upper end of the opening, a shape having a width in a first direction parallel to the surface of the substrate, and a width in a second direction parallel to the surface of the substrate and orthogonal to the first direction. The widths in the first and second directions are different from each other. The shape is capable of drawing, at each point on a circumference of the opening at the upper end, a circle of 0.6d in diameter which contacts the circumference at the point and does not include a portion outside the opening.