In a non-reciprocal circuit element, first to third center conductors intersect one another in an insulated state around a microwave magnetic body, and first ends of the first to third center conductors define first to third ports. A first capacitance element is connected to the first center conductor in parallel and a second capacitance element is connected to the second center conductor in parallel, and the other ends of the first to third center conductors are connected to one another and are grounded via a first inductance element and a third capacitance element that are connected in series. A second inductance element is connected to one end of the center conductor in parallel, and the other end of the second inductance element is grounded. A fourth capacitance element is connected to a connection point between the one end of the center conductor and the second inductance element, and the other end of the fourth capacitance element is connected to a third terminal.