At the corner part S0, a conductor except the conductor patterns 36, 37 does not exist on each of the wiring substrates 21, 22.

Subsequently, each conductor formation region of the first wiring substrate 21 and the second wiring substrate 22 is described.

FIG. 8A is a bottom view of the first wiring substrate 21.

In the example of FIG. 8A, a first conductor formation region R1 is demarcated on the lower surface 21a with avoiding a first corner part S1 of four corners of the first wiring substrate 21. The first conductor formation region R1 is a region in which the first ground pattern 31 and the first signal line 31a are formed. In this case, at the first corner part S1, a first dielectric region E1 in which a conductor such as the first ground pattern 31 and the first signal line 31a does not exist is demarcated.

The first dielectric region E1 is a rectangular region, as seen from above, and a length of a short side thereof is about 3 mm to 5 mm and a length of a long side is about 5 mm to 10 mm, for example. This also applies to second to fourth dielectric regions E2 to E4, which will be described later.

FIG. 8B is a top view of the first wiring substrate 21.