A filet F is added to a portion constituting a corner portion C equal to or smaller than 90null in a crossing portion X of wiring patterns 58b, 58c and 58d, and a wiring pattern 58 is formed. Since the filet F is added, the wiring patterns are not made thin and are not disconnected in the crossing portion X. Further, since there is no stress concentrated to the crossing portion X, disconnection is not caused in the wiring patterns and no air bubbles are left between the crossing portion X of the wiring patterns and an interlayer resin insulating layer so that reliability of a printed wiring board is improved.