The present invention aims to simulate a response more similar to a actual machine while inhibiting load increase in analog operation. Program configuration of the present invention is a component of a simulation program for circuit design, which is executed by a computer. The computer includes an operation portion, a storage portion, a manipulation portion, and a display portion, so that the computer exerts a function of a circuit design simulator, and as a macro model of an operational amplifier for use in the circuit design simulator, enabling the computer to act by simulating a response of the operational amplifier on the circuit design simulator. The macro model of the operational amplifier includes a control portion (LMT1) for generating output exception in the event of input exception or power supply exception of the operational amplifier.