A printed circuit board has a printed wiring board and a semiconductor package mounted on the printed wiring board. The printed wiring board and the semiconductor package are connected with a plurality of solder balls. An underfill material covering the plurality of solder balls is filled between the printed wiring board and the semiconductor package. The underfill material has a relative dielectric constant of 8.6 or more and 54.4 or less. Thus, crosstalk noise generated in wiring in the out-of-plane direction is reduced without increasing the mounting area.