A computer-aided design method of an integrated circuit includes: calculating current dissipation consumed by logic elements, in a ladder network embracing a plurality of current paths connected between subject first- and second-potential-level power supply wiring; analyzing a tolerable electro-migration current of the subject first-potential-level power supply wiring; analyzing an interval voltage drop between a control point and a specific position on the subject first-potential-level power supply wiring; and comparing a summation of through-currents flowing the logic elements from the control point to the specific point, with the tolerable electro-migration current, and comparing the interval voltage drop with a tolerable voltage drop to determine an optimum location of a via configured to supply power from the subject first-potential-level power supply wiring to the logic elements.