PURPOSE: To obtain a complete shielding effect by simple constitution by electrically connecting a power line and a cap by forming a side-face through-hole electrically connected to the power line for a multilayer printed interconnection board to the multilayer printed interconnection board.

CONSTITUTION: A side-face through-hole 22 is shaped to a multilayer printed interconnection board 1, and the side-face through-hole 22 is connected electrically to internal layer conductors 61, 62 for the multilayer printed interconnection board 1. Regarding the position of a cap 50 corresponding to the side-face through-hole 22, the cap 50 and the internal layer conductors 61, 62 for the multilayer printed interconnection board 1 are connected electrically by setting up the cap 50 for sealing and shielding molded so as to be electrically connected to the side-face through-hole 22. Accordingly, the intrusion of electromagnetic noises to the electronic circuit block from the outside and the radiation of electromagnetic noises to the outside from the electronic circuit block can be prevented.