A printed wiring board includes a mounting conductor layer including first and second electrodes, a connection conductor layer including connection wirings such that the connection wirings connect the first and second electrodes, a resin insulating layer formed between the mounting conductor layer and the connection conductor layer and having openings, and connection via conductors formed in the openings of the resin insulating layer and including first and second connection via conductors such that the first connection via conductors electrically connect the first electrodes and the connection wirings and the second connection via conductors electrically connect the second electrodes and the connection wirings. The resin insulating layer includes inorganic particles and resin. The inorganic particles include first inorganic particles forming inner wall surfaces in the openings and second inorganic particles embedded in the resin insulating layer. Shapes of the first inorganic particles are different from shapes of the second inorganic particles.