To realize a target band stop characteristics with a simple circuit constitution by cascade connecting plural serial/parallel resonance circuits, composed of a parallel resonance part and a capacitance serially connected to a parallel resonance part through a serial inductance.

Target asymmetrical frequency band-stop characteristics are set to prescribed frequency characteristics. Then, the circuit network function of a standardized high-pass filter, provided with asymmetrical standardized high pass characteristics is obtained, and frequency conversion is performed to the standardized high-pass filter. Then, narrow-band approximation near the center frequency of the target asymmetrical frequency characteristics is performed, and this band-stop filter provided with the asymmetrical frequency characteristics converted to an actual circuit element is realized. For the asymmetrical band-stop filter obtained, a reactance element serially connected to the parallel resonance part is the capacitance, and the reactance element cascade connected to the plural serial/parallel resonance circuits is the inductance.