PURPOSE: To quickly determine a rough wiring route which is good in the general situation.

CONSTITUTION: A network to express the positional relation of a line segment group contained in each rough wiring of an integrated circuit is generated by a line segment extracting means P1 and an assignment network generating means P2. Next, an optimal solution in a flow in which there is the possibility of the existence of inconsistency but all the line segments are taken into consideration is obtained by a minimum cost flow generating means P3. Next, in the case that the existence of the inconsistency in the flow is judged by a flow inconsistency existence judging means P4, and there is the inconsistency, the set of inconsistency canceling loops capable of canceling the inconsistency is extracted by a flow inconsistency canceling loop extracting means P5. Next, a flow updating means P6 selects the optimal loop in the extracted set of the inconsistency canceling loops. Finally, the flow made free from the inconsistency is converted into the new rough wiring route by reassigning the line segment by a line segment re-assigning means P7.