PURPOSE: To obtain a switched capacitor filter (cf) reduced the number of capacitors and its wiring area and variable at its transmitting function by using variable capacitors for obtaining a required capacitor value by binary weighted capacitors.

CONSTITUTION: The data of a capacitor value for obtaining the necessary transmitting function are written in an ROMB. The combination of analog switches S1∼Sm is determined in accordance with address signals a1∼an to obtain a required capacitor value. The transmitting function-variable SCF can be obtained by using the variable capacitors for the variable capacitors of the SCF. Consequently, the number of capacitors and the number of analog switches can be reduced. In addition, the area of wiring can be reduced.