PURPOSE: To reduce the harmful spurious response and the characteristic dispersion as well as to realize miniaturization of the filter by using the 2nd-style flexion lateral vibration tuning bar for the pole-use resonator which couples the additional couplers.

CONSTITUTION: The 2nd-style flexion lateral vibration is applied for pole-use resonators 3' and 9' which connect folding resonator 6 to additional couplers 20' and 21'. And the 1st-style flexion lateral vibration is adapted for other main resonators 4, 5, 7 and 8 each. Main couplers 12∼19 are given the butt welding at the center of each vibrating belly point of main resonators 4, 5, 7 and 8, pole-use resonators 3' and 9' plus folding resonator 6 respectively. While the butt welding is given to additional resonators 20' and 21' at the center of the belly lines of resonators 3' and 9' and also at the outer edge area of resonator 6 respectively. As a result, no coupled vibrating force affect resonators 3' and 9', thus reducing occurrence of the spurious response. Furthermore, the effective length can be stabilized due to the butting, thus ensuring the stabilized characteristics.