A printed wiring board includes a core insulation layer having via conductors through the core layer, a first structure including an interlayer insulation layer on first surface of the core layer and having via conductors through the interlayer layer in the first structure, and a second structure including an interlayer insulation layer on second surface of the core layer and having via conductors through the interlayer layer in the second structure. The interlayer layers have dielectric constants set to be 4.0 or lower for signal transmission at frequency of 1 GHz, the core layer has thermal expansion coefficient at or below Tg set lower than thermal expansion coefficients of the interlayer layers at or below Tg, the coefficient of the core layer at or below Tg is set to be 75 ppm/° C. or lower, and the conductors in the interlayer layers are stacked on the conductors in the core layer.