PURPOSE: To accurately eliminate burrs with laser beam or cleaning solution by determining the shape of cross sectional area of an inner lead in such a manner that the shape is sequentially set larger at least by 10% or more of the thickness of the lead from the one side to the other side surface.

CONSTITUTION: Insulating base materials 13 on which conductor patterns 15 are formed are integrated at both surfaces. Many leads 11 having an inner lead 11a electrically connected with a part of the conductor pattern 15 through a through-hole 16 are also provided. In particular, the shape of cross-sectional view of the part projected from the end edge of the insulating base material of at least the inner lead 11a is determined in such a manner that a width of lead of the one side surface is sequentially determined larger by at least 10% or more of thickness of the lead than the width of the lead of the other side surface. The space between the inner leads 11a is sequentially set smaller from the one side to the other side. Thereby, burrs 14 may be eliminated accurately by laser beam or cleaning solution.