PURPOSE: To control a partial characteristic impedance by providing conductive dead-end holes which are arranged in corner parts of a logic signal circuit to match the characteristic impedance of the logic signal circuit.

CONSTITUTION: After pair layers 9 are formed, outer layers of single-sided plates 10 are arranged in first and sixth layers, and they are laminated with a prepreg 4 between them, and a prescribed wiring board 5 is obtained by heating and pressure. Conductive dead-end holes 3a are arranged in corner parts of the logic signal circuit of the inner layer to eliminate mismatching of the characteristic impedance, thus obtaining the printed board having a uniform characteristic. The size, the number, and the depth of conductive dead- end holes 3a are changed to change a capacity C to the logic signal circuit, and as the result, the characteristic impedance can be controlled based on relations of characteristic impedance Z0=(L/C)1/2.