A multilayer semiconductor device includes first wirings extending in a first direction and arranged adjacent to each other in a second direction. Dummy wirings are arranged between the first wirings and the second wiring at crossing points between first virtual linear lines extending in a third direction and second virtual linear lines extending in a fourth direction. The third and fourth directions are neither parallel nor orthogonal to the first and second directions. The dummy wirings have a first, a second, and a third dummy wiring. Centers of the second and third dummy wirings are nearest to a center of the first dummy wiring relative to others of the dummy wirings. The respective centers of the first, second, and third dummy wirings are aligned on a third virtual linear line extending in a fifth direction neither parallel to nor perpendicular to the first and second directions.