Abstract: The purpose of the invention is to determine an optimum initial value to be input to a test pattern generator in order to achieve efficient testing of an integrated circuit. To achieve this purpose, a minimum test length is obtained by performing a fault simulation and a reverse-order fault simulation using an arbitrarily given initial value; the next initial value that is likely to yield a test length shorter than the minimum test length is computed and a fault simulation is performed using the thus computed initial value; and the next initial value that is likely to yield a test length shorter than that test length is computed and a fault simulation is performed using the thus computed initial value. By repeating this process, an initial value that yields the shortest test length is obtained.