A semiconductor device includes a first pattern and a plurality of second patterns arranged at equal intervals. When the distance of the space between the first pattern and the second pattern closet to the first pattern is larger than a first distance, a plurality of dummy patterns are arranged in the space with shapes and intervals similar to those of the second patterns. When the distance of the space is equal to or less than the first distance and larger than a second distance, the dummy pattern is spaced from the second pattern closest to the first pattern, and extends toward the first pattern to be brought into contact with the first pattern. When the distance of the space is equal to or less than the second distance, the dummy pattern is spaced from the second pattern closest to the first pattern, and is connected to the first pattern.