A well potential supply region is provided in an N-type well region of a cell array. Adjacent gates disposed in both sides of the well potential supply region in the horizontal direction and adjacent gates disposed in further both sides thereof are disposed at the same pitch. In addition, an adjacent cell array includes four gates each of which is opposed to the adjacent gates in the vertical direction. In other words, regularity in the shape of the gate patterns in the periphery of the well potential supply region is maintained.