PURPOSE: To equalize the DC offset voltage included in an output when the characteristic is changed over by providing a switched capacitor charged with an output signal of a sampling switch and an integration means or the like comprising an integration capacitor integrating the charged electric charge of the switched capacitor at a prescribed period and an operational amplifier.

CONSTITUTION: A resistance division circuit 30 inputting an analog signal and outputting N-set of different voltages through resistance division, changeover switches SC1∼SCN using a control signal to select one output among outputs of said resistance division circuit 30, and a sampling switch Sa sampling the output signals from the changeover switches SC1∼SCN at a prescribed period are provided. Further, the switched capacitor 10 charged with the output signal of the sampling switch Sa, and the integration means comprising an integration capacitor 20 integrating the charged electric charge of the switched capacitor 10 at a prescribed period and one operational amplifier A are provided. Thus, the DC offset voltage appearing at the output at characteristic changeover is made equal, resulting that the DC offset is adjusted entirely totally thereby simplifying the offset adjusting circuit.