A nonreciprocal circuit element includes a magnetic assembly including a ferrite magnetic body, a common electrode, and three central conductors; capacitors connecting to the respective central conductors; a permanent magnet which applies a DC bias magnetic field to the magnetic body; and a metal case which accommodates the magnetic assembly, the capacitors, and the permanent magnet, the metal case functioning as a magnetic yoke. The saturation magnetic flux density of at least a portion of the metal case and the residual magnetic flux density of the permanent magnet have negative temperature coefficients. Moreover, the portion of the metal case is composed of a magnetic material having a larger absolute value of the temperature coefficient of the saturation magnetic flux density than the absolute value of the temperature coefficient of the residual magnetic flux density of the permanent magnet in the range of −35° C. to +85° C.