The present invention provides a circuit simulation method of executing a high-precision circuit simulation. A voltage fluctuation analysis step at a gate level is executed (step S2). The voltage fluctuation analysis step at the gate level is executed on an entire chip TP. Next, a step of obtaining waveforms of power supply voltage and ground voltage (Vss) according to the voltage fluctuation analysis step is executed (step S4). Subsequently, a signal analysis step at a transistor level is performed (step S6). The signal analysis step at the transistor level is performed in an area narrower than the entire chip TP, for example, on one or more functional modules. After that, a step of obtaining a signal analysis result according to the signal analysis step is executed (step S8).