Route searching method and storage medium

This application claims the benefit of a Japanese Patent Application No.11-320219 filed Nov. 10, 1999, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference. A route searching method is used for circuit design, and includes a step of setting, with respect to each pin, a corresponding flag of a pass flag which indicates that a pin is passed, a searching flag which indicates that a pin is being searched, and a branch flag which indicates that a pin is a branch point, and a step of determining a direction of a route search depending on each flag which is set with respect to each pin.