<p>An irreversible circuit element includes: a first inductance element (L1) arranged between a first I/O port (P1) and a second I/O port (P2); a first capacitance element (Ci) connected in parallel to the first inductance element (L1) to constitute a first resonance circuit; a resistor element (R) connected in parallel to the first parallel resonance circuit; a second inductance element (L2) arranged between the second I/O port (P2) of the first resonance circuit and the earth; a second capacitance element (Cfa) connected in parallel to the second inductance element (L2) to constitute a second resonance circuit; a third inductance element (Lg) arranged between the second resonance circuit and the earth; and a third capacitance element (Cfb) connected between the second I/O port (P2) of the first resonance circuit and the earth.</p>
