A variable gain amplifier circuit in which a feedback circuit that feeds back the output signal of an amplifier from its output terminal to its input terminal is composed of an FET. The gate terminal of the feedback FET is connected to the output terminal of the amplifier through a capacitor, and the source terminal of the feedback FET is connected to the input terminal of the amplifier. The gain of the amplifying circuit is controlled by varying the transconductance of the feedback FET by controlling a bias voltage applied to the gate or drain terminal of the feedback FET. This makes it possible to control the gain independently of the physical dimension of the feedback FET, and at the same time, to prevent the input signal from being transmitted from the input side to the output side through the feedback circuit.