A semiconductor device includes a semiconductor substrate including a main surface; a plurality of first interconnections formed in a capacitance forming region defined on the main surface and extending in a predetermined direction; a plurality of second interconnections each adjacent to the first interconnection located at an edge of the capacitance forming region, extending in the predetermined direction, and having a fixed potential; and an insulating layer formed on the main surface and filling in between each of the first interconnections and between the first interconnection and the second interconnection adjacent to each other. The first interconnections and the second interconnections are located at substantially equal intervals in a plane parallel to the main surface, and located to align in a direction substantially perpendicular to the predetermined direction.