Abstract: When connecting a second printed substrate 3 with a first printed substrate 2, a plurality of first connection patterns 4s, 4b, for example, including through holes 2h are provided on the first printed substrate 2, a plurality of second connection patterns 5a, 5b facing the first connection patterns 4a, 4b are provided on an under surface 3d of the second printed substrate 3, and the first connection patterns 4a and the second connection patterns 5a are soldered using a reflow system or a flow system, thereby providing simplification, miniaturization, and reduction of cost together with noise reduction, lower loss, and high reliability.