A printed wiring board includes a first resin insulating layer, a second resin insulating layer formed on a surface of the first layer, and a conductor layer formed on the surface of the first layer such that the second layer is covering the conductor layer and that the conductor layer includes first, second, third, fourth, fifth, and sixth circuits such that the third and fourth circuits are sandwiching the first circuit and that the fifth and sixth circuits are sandwiching the second circuit. Widths between the first and third circuits and between the first and fourth circuits are 5 μm to 14 μm, and when a width between the second and fifth circuits and a width between the second and sixth circuits is 20 μm or more, the upper surface of the first circuit, and the upper surface and side walls of the second circuit are formed to have unevenness.