To prevent deterioration in the gain control extent at a high frequency, deterioration in the distortion improvement effect and generation of parasitic oscillation due to a capacitor provided to a gain control FET for improving distortion at the gain control.

An RF signal inputted from input terminals 1, 2 is amplified by amplifier FRETs 5, 6 and the amplified signal is outputted from output terminals 3, 4. A gain at this time is controlled by changing a resistance of a variable resistor 14 in response to a gain controlled voltage applied from an input terminal 21. The resistance is changed by changing a channel resistance of a gain control FET 15 based on the gain controlled voltage and in order to improve distortion at gain control here, a capacitor 24 is provided between a gate of the gain controlled FET 15 and a connecting point of gain controlled variable adjustment resistors 18, 19. Based on such the connection, the capacitor 24 disregards the effect on the channel resistor of the gain control FET 15.