A wiring substrate includes a first conductor layer including wirings, an interlayer insulating layer formed on and covering the first conductor layer, a wiring layer formed in the interlayer insulating layer and including wirings, a second conductor layer formed on the interlayer insulating layer and including wirings, and a via conductor formed in the interlayer insulating layer such that the via conductor is penetrating through the interlayer insulating layer and connecting the first and second conductor layers. The interlayer insulating layer includes first and second insulating layers such that the wiring layer is formed on a surface of the first insulating layer, and the wiring layer is formed such that an aspect ratio of the wirings in the wiring layer is in the range of 2.0 to 6.0 and that aspect ratios of the wirings in the first and second conductor layers are in the range of 1.0 to 2.0.