If there are a plurality of activation paths on which a signal propagates during a delay test, multiple-input cells receiving two or more activation paths are extracted by an extraction unit. For the extracted multiple-input cells, whether there is a possibility of occurrence of a multiple-input switching in a multiple-input cell is determined by a determination unit, based on an input timing to each signal multiple-input cell in the two or more activation paths. Then, an occurrence situation of a multiple-input switching is analyzed as one delay cause by an analysis unit, based on a determination result by the determination unit and a result of the delay test.