PURPOSE: To provide a trap at a desired position in using the titled filter as a VIF filter or an SIF filter by determining a number of pairs of normal electrodes according to a specific formula.

CONSTITUTION: The normal electrode 14 whose cross width is 10λ0 or below (λ0 is the wavelength of a surface wave at the center frequency of the passing characteristic) is formed to one major face of a piezoelectric substrate 12. In this case, the number of pairs N of the normal electrodes 14 is expressed in equation I, where f0 is the center frequency of the pass characteristic and Δf is the band width of the passing characteristic. Since the band width is widened in this way, the trap is formed at a desired frequency. In using the surface acoustic wave as a filter such as a VIF filter or an SIF filter, the video trap or the audio trap of an adjacent channel to a reception channel are formed at a desired frequency thereby improving the characteristic of the VIF filter and the SIF filter.