A surface acoustic wave filter (cascaded dual mode SAW filter) includes three IDT electrodes disposed adjacent to each other along the propagation direction of a surface wave on a piezoelectric substrate and two primary-tertiary longitudinally-coupled dual mode SAW filters cascaded and constructed by arranging grating reflectors on both sides of three IDT electrodes. At least a pair of electrode fingers are thinned out from the IDT electrodes disposed outside, and floating electrodes are then disposed.