PURPOSE: To compensate automatically a linear gain varying with an emitter current by connecting a variable resistance element, whose resistance value varies with an emitter current value, as a collector load in the circuit controlling a limiting level by the emitter current.

CONSTITUTION: In the transistor (Tr) amplitude limiter which controls an amplitude limiting level by an emitter current, variable element z is connected as a collector load to the collector of Tr6 of the amplitude limiting circuit composed of transistors 5 and 6 supplied with signals of input terminal (a). Then, the resistance value of variable element z is made to vary with the emitter current, and the variation of the emitter resistance of the Ts inself caused by the emitter current is suppressed, so that linear gains of Trs 5 and 6 operating by the emitter current will be compensated automatically.