First and second paths (I,II) are connected in parallel between an input terminal (IN) and an output terminal (OUT). A high-pass filter (HPF) is provided in the first path (I). A low-pass filter (LPF) is provided in the second path (II). A switch (SW1-SW4) connects one of the high-pass filter (HPF) and the low-pass filter (LPF) to the input terminal (IN) and the output terminal (OUT) and disconnects the other. A transmission line (TL1,TL2) is provided on the first and second paths (I,II) respectively. A line length of the transmission line (TL1,TL2) is adjusted such that a resonance caused due to circuit constants of the high-pass filter (HPF) and the low-pass filter (LPF) and capacitance obtained when the switch (SW1-SW4) is OFF is shifted to a communication frequency band.