To adjust the passing bandwidth of the resonator type surface acoustic wave filter.

Serial arm elements 30S-1, 30S-23, and 30S-4 pass signals of frequencies above a resonance frequency and below an antiresonance frequency well and do not pass frequencies above the antiresonance frequency well. Parallel arm elements 30P-12 and 30P-34 pass frequencies above the resonance frequency and below the antiresonance frequency well and do not pass frequencies below the resonance frequency well. Consequently, this resonator type SAW filter pass signals of frequencies from the resonance frequency of the parallel arm elements 30P-12 and 30P-34 to the antiresonance frequency of the serial arm elements 30S-1, 30S-23, and 30S-4 to serve as a band-pass filter. A piezoelectric substrate 31 has a large electromechanical coupling coefficient, so the bandwidths of serial arm resonators 40S-1, 40-S-23, and 40S-4 and parallel arm resonators 40P-12 and 40P-34 become unnecessarily wide. Therefore, capacitors 50S-1, 50S-23, 50S-4, 50S-12, and 50P-34 are connected to those respective resonators in series to reduce and adjust the bandwidth.