PURPOSE: To miniaturize the form of a coil and to shorten the control time by compensating the drop of attenuation degree of an attenuation area which is produced when an attenuation pole near the pass area of an LC ladder type BPF is replaced with a crystal resonator.

CONSTITUTION: This circuit is provided with a parallel resonance circuit 5 of parallel arms containing a crystal resonator, parallel resonance circuits 3 and 4 of the same resonance frequency, a crystal resonator (equivalent circuit) 6, a coil L8, and a series resonance cicuit 9 for compensation having the same frequency as those of circuits 3, 4 and 5. Then the circuit 9 having the same resonance frequency as the drop frequency of attenuation degree is connected to the tap of the coil L8. Thus the drop of the attenuation degree of a frequency f3H is reduced to satisfy the rated characteristics. This can miniaturize the coil form of an LC resonance circuit of parallel arms and also needs no fine adjustment.