A notch portion 7A is disposed on a formation surface of a wiring pattern 7 and is located in a contact point with a wiring pattern 9 of an outside substrate 8, so that a solder 9a melted by reflow soldering slowly flows up along an edge of the notch portion 7A, improving a solder-joint performance. The notch portion 7A is formed in a recess shape as formed by cutting away the substrate 6 and as a result, the melted solder stays in the recess portion, which prevents the melted solder from moving up over the notch portion 7A.