A non-reciprocal circuit device comprising a first inductance element L1 disposed between a first input/output port P1 and a second input/output port P2, a first capacitance element Ci parallel-connected to the first inductance element L1 to constitute a first resonance circuit, a resistance element R parallel-connected to the first parallel resonance circuit, a second inductance element L2 disposed between a second input/output port P2 of the first resonance circuit and a ground, a second capacitance element Cfa parallel-connected to the second inductance element L2 to constitute a second resonance circuit, a third inductance element Lg disposed between the second resonance circuit and the ground, and a third capacitance element Cfb disposed between a second input/output port P2 of the first resonance circuit and the ground.