Abstract: Provided is a circuit analysis tool having a function that enables the use of a high-accuracy simulator of SPICE2 or the like while reducing the time required for processing from the first simulation. The circuit analysis tool of the present invention distinguishes between a circuit element in which voltage and current values or a signal value change or changes in response to the input of a test signal and a circuit element in which no change of the values or value occurs on the basis of connection information of a semiconductor integrated circuit. The circuit element in which no change of the values or value occurs in response to the input of the test signal is replaced by an equivalent constant voltage terminal or grounding terminal, reducing the number of circuit elements to be subjected to simulation to be continuously executed (the amount of data of circuit information).