PURPOSE: To switch the transmission characteristic and also to prevent deterioration of noise rejection ratio by supplying a ground potential to a capacitor not selected.

CONSTITUTION: Switches S10∼S13 and S30∼S33 are constituted by transfer (changeover) switches. Then a ground potential is fed to a contact at the non- selection side. Only the switch S10 is herein turned on and a capacitor C10 is selected. Then the switches S11∼S13 are turned off and a ground potential of the circuit is fed to switch side electrodes of capacitors C11∼C13 of non-selection. Furthermore, only the switch 30 is turned on and a capacitor C30 is selected. Moreover, when the S31∼S33 are turned off, the ground potential of the circuit is fed to the switch side electrodes of the capacitors C31∼C30 of non- selection.