a multi - layer printed circuit board has a through hole extending therein outside the mounting portion of a component mounted on the surface layer of the board . the component has a lead pad on the surface layer of a first printed circuit board and a modification pad on the surface layer between the through hole and the lead pad . the through hole extends through the first board to inside the mounting portion via a pattern of an internal wiring layer of the board . a second printed circuit board is joined to the first board at the internal layers of each to form a unitary integrated circuit board . another through hole extends through the first and second boards inside the mounting portion of the integrated printed circuit board . the pattern and a selected wiring layer of the second board are thereby connected via the other through hole . additional through holes extend through the second board and interconnect the layers of the second board . the additional through holes are positioned in areas devoid of the first - mentioned through hole .