Cells are formed on a substrate. First and second cell power wiring lines extend in a first direction on the substrate. First and second intermediate layer power wiring lines are formed on the first and second cell power lines. First upper layer power wiring lines are formed on the first and second intermediate layer power lines. The first upper layer power wiring lines extend in a second direction crossing the first direction at right angles. First contact members are formed between the first cell power lines and the first upper layer power lines. Second contact members are formed between the second cell power lines and the first upper layer power lines. The second contact members are arranged at positions shifted from a straight line which passes through the first contact members in the first direction and a straight line which passes through the first contact members in the second direction.