A Q-factor of a resonator at a high frequency is improved. An insertion loss of a filter using such a resonator and steepness of the filter are improved. A plurality of surface acoustic wave resonators including an interdigital transducer and reflecting electrodes provided on both sides thereof are connected in parallel on a piezoelectric substrate. Resonance frequencies of the surface acoustic wave resonators are rendered equal among all the resonators connected in parallel. In this way, the Q-factor of the resonance can be improved. A surface acoustic wave filter using such surface acoustic wave resonators is formed in order to improve the insertion loss and the steepness.