PURPOSE: To minimize a total capacity value by providing a switch at both ends of a switched capacitor provided at an input part and a feedback part, making it dead to a parasitic capacity and providing an inverting amplifying circuit to phase-invert the output of the capacitor.

CONSTITUTION: Capacitors 2 and 3 come to be the switched capacitors dead to the parasitic capacity because both ends are separated from other circuit by switches 8∼11 and the period connected to the earth exists at respective ends. The signal inputted from an input terminal IN is sampled by the capacitor 2 and enters an operational amplifier 7. Here, the phase inversion is executed, coefficient multiplication is executed, the output is executed, a phase inverting circuit is started by capacitors 1 and 5 and an operational amplifier 6 and the coefficient multiplication is executed and the output is executed. The output OUT is sampled by the capacitor 3 and the inverting input of the operational amplifier 7 is obtained.