1. A method for deriving an equivalent circuit model of a capacitor that is formed by a resistive element, a capacitive element,

and an inductive element, the method comprising:

expressing, by a computer, a rate of change in a characteristic value of a voltage-dependent element being one of the resistive

element, the capacitive element, and the inductive element, the voltage-dependent element having a value that changes as a

direct current voltage is applied to the capacitor, the value being a dimensionless coefficient on the basis of a rate of

change in the characteristics of the capacitor attributable to a material of the capacitor;

multiplying, by the computer, the characteristic value of the element, of which the characteristic value changes in response

to the direct current voltage being applied to the capacitor, held while the direct current voltage is not applied by the

dimensionless coefficient; and

correcting, by the computer, the characteristic value of the element to a value in accordance with the direct current voltage

applied to the capacitor,

wherein the equivalent circuit model is formed by one of a main resonant circuit, a secondary resonant circuit, a capacitive

circuit, and an inductive circuit, the main resonant circuit being formed by connecting a resistive element, a capacitive

element, and an inductive element in series, the secondary resonant circuit being formed by connecting a resistive element,

a capacitive element, and an inductive element in parallel, the capacitive circuit being formed by connecting a resistive

element and a capacitive element in parallel, the inductive circuit being formed by connecting a resistive element and an

inductive element in parallel; or the equivalent circuit model is formed by connecting some of the main resonant circuit,

the secondary resonant circuit, the capacitive circuit, and the inductive circuit in series.