Time-axis data that include the peak waveform and the clock frequency of the power supply current when the LSI is switched are inputted to the LSI information input unit, and the LSI equivalent circuit creation unit creates an equivalent circuit of the LSI on the basis of the time-axis data. The time-axis/frequency-axis conversion unit converts the time-axis data to frequency-axis data. The equivalent circuit synthesis unit synthesizes the equivalent circuits of the printed wiring substrate, the power supply regulator, and the LSI to create a single equivalent circuit; the frequency-axis circuit analysis unit performs frequency-axis analysis of the single equivalent circuit; and the frequency-axis/time-axis conversion unit converts the results to time-axis data. The amount of fluctuation of the power supply voltage of an integrated circuit device can thereby be evaluated in a short time.