To provide the microwave and milliwave circuit which can be stabilized by suppressing parasitic oscillation of an active element.

Of the microwave and milliwave integrated circuit, a route transmission line 1 (characteristic impedance Z0) is provided with an open stub 3 which has λ0/4 length (λ0: wavelength) at frequency f0, and a transmission line 2 is arranged nearby the open stub 3 to a length of about 15λ0/64 from a position which is at a distance of about λ0/64 from the route transmission line to constitute a coupling line part; and both the ends of the transmission line 2 are grounded through actual resistances 4 and 4 having a resistance value R so that Z0/2<R<2Z0.