PURPOSE: To obtain sudden gain characteristics in an attenuated region at the high band side of frequency by forming a bicut filter with a double primary conversion type integrator and a forward integrator.

CONSTITUTION: An input terminal 1 is connected to an inverse input terminal of an operational amplifier 4 via a switched capacitor 3, and an inverse input terminal of an operational amplifier 8 is connected to the output terminal of the amplifier 4 via a switched capacitor 7. The non-inverse input terminal of the amplifier 8 is grounded. Then a switched capacitor functioning as a feedback reistance is connected respectively between the output terminal of the amplifier 8 forming a forward integrator and the inverse input terminal of the amplifier 4 forming a doulde primary conversion type integrator and between the output terminal and inverse input terminal of the amplifier 4. For the transmission functions of these switched capacitor filters, the trap characteristics are produced at 1/2 sampling frequency. This improves the so-called sharp-cut properties of the switched capacitor filter.