A semiconductor device includes a lower wiring layer, having signal lines and power supply lines extending in a Y-direction; an upper wiring layer having signal lines and power supply lines extending in an X-direction; via conductors provided in first overlap regions where corresponding signal lines overlap each other; and via conductors provided in second overlap regions where corresponding power supply lines overlap each other. The width in the X-direction of the first regions is wider than the widths in the X-direction of the second regions. Therefore, in the first regions, a plurality of via conductors can be provided. Moreover, the power supply lines are divided in the Y-direction to avoid interference with the first regions. On a plurality of lower-layer lines, two vias are placed at a minimum pitch containing one via.