PURPOSE: To establish the gain control amplifying circuit operated with high performance independently of the characteristics of amplifier, by inserting the second amplifier to the negative feedback circuit of the first amplifier.

CONSTITUTION: The input signal E1 from the terminal 13 is fed to the first amplifier 15 via the resistor R5 and outputted as the output E2 at the terminal 16. The second amplifier 19 and the first transistor 21 for gain control are inserted to the feedback circuit of the amplifier 15 and the second transistor 18 for gain control is inserted to the feedback circuit of the amplifier 19. Further, the gain of this circuit is determined with the expotential function of the DC voltage Vc1 fed to the control input terminal 22.