A printed wiring board includes a resin insulating layer including resin and particles, and a conductor layer formed on a surface of the resin insulating layer. The particles in the resin insulating layer include first particles and second particles such that the first particles are partially embedded in the resin and the second particles are completely embedded in the resin, and the resin insulating layer is formed such that the first particles has exposed surfaces exposed from the resin and covered surfaces covered by the resin, respectively, the surface of the resin insulating layer includes the first exposed surfaces, and a ratio of a second area to a first area is in a range of 0.1 to 0.25 where the first area is an area of the surface of the resin insulating layer, and the second area is obtained by summing areas of the exposed surfaces of the first particles.