To calculate electromagnetic field intensity emitted by an electric circuit device at high speed while maintaining high precision.

A sample calculation processing part 4 calculates mutual impedance in a sampling frequency without using an approximate expression. An approximate coefficient derivation processing part 5 calculates an approximate coefficient with an LU analysis method in accordance with the approximate expression that is constituted of the polynomial of the frequency, which is expressed by the approximate coefficient and the frequency, and that shows mutual impedance. An approximate calculation processing part 9 calculates the mutual impedance in the designated frequency with the approximate expression by using the approximate coefficient. An electromagnetic flow calculation processing part 10 calculates a current value flowing in respective elements by using the mutual impedance. An electromagnetic field calculation processing part 11 calculates an electric field and a magnetic field by using the current value.