PURPOSE: To enhance hole position accuracy at the machining time of a drill hole by means of an NC boring machine, and, at the same time, enhance quality of a printed wiring board and productivity by increasing stacking number of copper-clad laminated boards.

CONSTITUTION: Copper-clad laminated bodies 2, 3 or plural copper-clad laminated bodies 2, 3 having, at least, conductive patterns in their internal layers are stacked up, and a backplate 11 whereon a groove in the form of grid or an uniform unevenness is proved is stacked up on the copper-clad laminated bodies 2, 3 on the side of a drill at the time of drilling, and performs drilling in this state.