A bandpass filter circuit 10 of the present invention includes: transconductance amplifier circuits 1 to 3; a common-mode feedback circuit 4 which outputs a first control signal to the transconductance amplifier circuit 1 so that a D.C. voltage level of a differential output of the transconductance amplifier circuit 1 is at a predetermined level; a common-mode feedback circuit 5 which outputs a second control signal to the transconductance amplifier circuit 2 so that a D.C. voltage level of a differential output of the transconductance amplifier circuit 2 is at a predetermined level; and capacitors C1 to C3. Each of the members are connected as shown in FIG. 1. With the configuration, a bandpass filter circuit capable of adjusting constants such as a Q-value is realized.