PURPOSE: To form a filter circuit passing a desired frequency signal by forming plural capacitors having substantially identical capacitance in the same semiconductor substrate by the same device process, forming a CMOS transistor (TR) so as to form plural switched capacitor circuits and connecting said switched capacitor circuits and the capacitors so as to form an LPF and an HPF with different cut-off frequency.

CONSTITUTION: The capacitor C1 is formed substantially as the same capacitance in the same semiconductor device by the same device process and a switch S11 is formed by the CMOS TR formed in the same semiconductor substrate. Then the switched capacitor circuits SC1, SC2 are formed by the capacitor C1 and the switch S11. When the switches S11, S12 are thrown sequentially from solid line states into dotted line states, a resistor R is set by the frequency of a clock signal Clk. Thus, a low-pass filter circuit F is formed by two resistors R and the capacitor C1. Further, when the switches S1, S2 are thrown in dotted lines, a high-pass filter circuit is formed.