PURPOSE: To obtain a reverse phase amplifier by connecting respectively blocks composed by connecting in parallel the circuit, in which two switches are con nected between a terminal and an earth respectively, to both poles of a capaci tor between the load input and the load input-output of an operational amplifier.

CONSTITUTION: A switch S1 is opened and closed by a clock and a switch S2 is opened and closed by a clock 2. A capacitor C1 and a capacitor C2 are the same capacity value and a capacitor C3 and a capacitor C4 are the same capacity value. Presently, when C1=C2=CR1 and C3=C4=CR2 are obtained, respectively blocks have the equal resistance value and a reverse phase amplifier can be equally obtained.