The present invention is directed to provide a low-power-consumption wide-range RF signal processing unit having a small chip occupation area. A semiconductor integrated circuit has, on a semiconductor chip, a resonant circuit including a first capacitor (1) having a capacitance (CR) which can be controlled by a first control signal (Vc10 of a first control terminal (101), and a gyrator (2, 5) for equivalently emulating an inductor (L) by including a second capacitor (3) having a capacitance which can be controlled by a second control signal (Vc2) of a second control terminal (102). The capacitance (CR) and the inductor (l) form a parallel resonant circuit. At the time of changing parallel resonant frequency, the capacitances of the first and second capacitors (1, 3) are coordinately changed. The parallel resonant circuit is suitable for an active load which is connected to an output node of an amplifier (q1).