Disclosed is a method of setting a process parameter for use in manufacturing a semiconductor integrated circuit, comprising correcting a first pattern by using process parameter information to obtain a second pattern, the first pattern being one which corresponds to a design layout of the semiconductor integrated circuit, predicting a third pattern by using the process parameter information, the third pattern being one which corresponds to the second pattern and which is to be formed on a semiconductor wafer in an etching process, obtaining an evaluation value by comparing the third pattern with the first pattern, determining whether the evaluation value satisfies a preset condition, and changing the process parameter information when the evaluation value is found not to satisfy the preset condition.