PURPOSE: To simplify the titled circuit and to reduce number of components by forming two phase shifters by a dual phase shift circuit using only one operational amplifier.

CONSTITUTION: Variable resistors R17, R21 constitute an input separating circuit separating an input signal IN. Resistors R19, R20 consititute a gain setting circuit dividing the input signal IN and setting the gain of operational amplifiers 6, 7. The gain setting circuit is connected in common to eacg in-phase input terminal (non-inverting input terminal)+ of the operational amplifiers 6, 7. Thus, a prescribed phase difference is obtained at a broad frequency band around the center frequency. Thus, the circuit is simplified and the number of components is reduced.