A plurality of lands is formed apart from each other on a surface of a package substrate. Another plurality of lands is formed apart from each other on a surface of a printed wiring board. The surface of the package substrate and the surface of the printed wiring board face each other. The plurality of lands and another plurality of lands are bonded to each other with solder having a height of 30% or less of a diameter of a solder bonding portion at the corresponding land. A ratio of a solder bonded area of at least each of lands, among another plurality of the lands, of which distance value to a corresponding one of the lands is larger than an average distance value between the lands and another lands, to a solder bonded area of the corresponding one of the lands is 56% or more and 81% or less.