A circuit board fabrication method comprising the steps of: forming first conductive interconnection 2 onto insulator substrate 1; applying resin film 41, which is to be interlevel insulator layer 42 for electrically insulating first conductive interconnection 2 and second conductive interconnection 6, onto insulator substrate 1; either making pillar-like member 3 stand on a prescribed position on first conductive interconnection 2 before applying resin film 41, or press fitting pillar-like member 3 into resin film 41 in such a manner as to reach either a surface vicinity of first conductive interconnection 2 or a portion of first conductive interconnection 2 after applying resin film 41; hardening resin film 41 to form interlevel insulator layer 42; pulling out pillar-like member 3 to form opening 5 in interlevel insulator layer 42; and (f) forming second conductive interconnection 6 onto interlevel insulator layer 42 in such a manner as to include opening 5.