PURPOSE: To raise the channel use ratio on a host layer and to reduce the non-wired number by selecting a prescribed through-hole model at the time of searching a wiring route and determining the wiring route to a layer which is apart more than two layers.

CONSTITUTION: In a wiring route automatic generation method, at first, wiring data is inputted (step 501) and the registration processing of a through-hole model is performed (step 502). Next, the number of nets is detected (step 503) and a wiring route search processing is performed (step 504). Further, an output processing is performed (step 505) and a wiring route automatic generation processing is terminated. Namely, by preliminarily storing the through-hole model in a common table, selecting a prescribed through-hole model at the time of searching the wiring route and determining the wiring route to a layer which is apart more than two layers based on the selection, the moving of the wiring route between multilayers can be performed one time.