Abstract: A SAW resonator filter apparatus includes attenuation characteristics which are steep in a frequency region from a pass band to a higher-frequency stop band without experiencing an increase in insertion losses and enlargement of the apparatus. First, second and third SAW resonator filters are disposed on a piezoelectric substrate and are connected in a cascade arrangement to each other. The first and third SAW resonator filters have interdigital electrodes formed of solid electrode fingers, while the second SAW resonator filter disposed between the first and third filters has interdigital electrodes formed of split electrode fingers. With this construction, the steep attenuation characteristics of the response in a higher frequency range appearing in the frequency characteristics of the second SAW resonator filter can be combined with the attenuation characteristics from the pass band to a higher-frequency stop band of the first and third SAW resonator filters.