PRINTED WIRING BOARD AND METHOD FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide a printed wiring board which easily and surely keep electrical connection between an interstitial via hole and a first conductive pattern on a surface side.SOLUTION: A printed wiring board comprises: a substrate having an insulation property; a first conductive pattern stacked on a surface of the substrate; a second conductive pattern stacked on a rear surface of the substrate; and an interstitial via hole passing through the first conductive pattern and the substrate. A cross-sectional shape of the interstitial via hole having a surface of the conductive pattern as a cut surface, is non-circular. It is preferred that the printed wiring board has a plurality of interstitial via holes, and cross-sectional shapes of a plurality of interstitial via holes have long axes along approximate same directions. The cross-sectional shapes may be nearly a polygonal shape or an elliptic face.