An equivalent circuit for a coil incorporated in a circuit simulator is a model of an equivalent circuit for a coil included in a circuit simulator for analysis of an electrical device including a coil forming a magnetic circuit. The equivalent circuit of a coil included in an electric motor or other electrical device is preferably comprised of a resistance component (R), induced voltage component (−dΦ/dt), and inductance component (L). The equivalent circuit of the inductance component is provided with a current source, a voltage extractor for extracting the voltage across the terminals of this current source, a current generator for determining the value of the current of the current source based on the value of the voltage output by this voltage extractor, and a current-carrying path connected in parallel to the current source and carrying a regenerative current at the time of off operation. By the above configuration, an electrical device including a coil can be analyzed and the iterative calculation at the time of handling nonlinear characteristic data becomes unnecessary. An actual model can be realized with variable values of the inductance element.