A printed wiring board includes: a core substrate having a core layer, first and second conductor layers, and through-hole conductors penetrating through the core layer and connecting the conductor layers; and first and second build-up layers each including an insulating layer, an inner side conductor layer, an outermost insulating layer, an outermost conductor layer, and a solder resist layer. Each of the conductor layers includes conductor circuits having substantially a trapezoid cross-sectional shape, and spaces between adjacent conductor circuits, and includes a metal foil, a seed layer, and an electrolytic plating film. The inner side conductor layers have the smallest minimum circuit width, the smallest minimum space width and the largest base angle among the conductor layers. The insulating layers have the smallest ten-point average roughness rz3, rz7 among the ten-point average roughness rz3, rz7, rz1, rz2, rz5 and rz9 of the core layer, insulating layers and outermost insulating layers.