To reliably connect electronic components to the wiring conductor of an external electric circuit board by improving the electrical insulation reliability between the metallization conductors of a through hole that can be cut straightly in the case of cutting and dividing into each wiring substrate region from a batch-process wiring board.

A plurality of nearly rectangular wiring board regions 2 which is cut by a split line 3 is arranged and formed on a mother board 1 made of dielectric in one piece vertically and horizontally, at the same time the through hole is formed on the split line 3, and the metallization conductor 5 containing 50-65 pts.wt. ceramic powder to metal powder is filled into the through hole.