A wiring processing apparatus decides each group formed by sorting signals that flow between component pins. Then, the wiring processing apparatus reads printed circuit board data and identifies a net cluster that belongs to each group. After a net cluster that belongs to each group is identified, the wiring processing apparatus refers to the printed circuit board data about the identified net cluster, and automatically creates each wiring route that indicates a wiring scanning area of the signal cluster in each group. Thus the wiring processing apparatus displays them on the printed board data. After the wiring route is automatically created, the wiring processing apparatus automatically creates wiring route information that corresponds to each wiring route, and controls them according to each wiring route.