Abstract: A variable gain amplifier for compensating for an amplitude frequency response characteristic of an input signal transmitted through a transmission path having a predetermined attenuation characteristic, includes a first amplifier for amplifying the input signal with a substantially flat amplitude frequency response characteristic, a second amplifier for amplifying the input signal with a predetermined amplitude frequency response characteristic corresponding to the attenuation characteristic of the transmission path, an adder circuit for reciprocally level-controlling the signals amplified by the first and second amplifiers so that a level of one of the signals is increased when a level of the other signal is reduced, and adding the level-controlled signals to each other, and an addition controller for variably setting a determination amount of level control performed by the adder circuit in accordance with a line length of the transmission path.