A surface acoustic wave apparatus includes an input terminal, an output
terminal, a plurality of acoustically coupled interdigital transducers
(IDT), and a phase rotating element (line or inductor) connected in
parallel with one or more IDT's. The acoustically coupled IDT's are
connected in series between the input and output terminals.
Alternatively, the acoustically coupled IDT's may include a series IDT to
which the phase rotating element is connected and which is connected in
series between the input and output terminals, and a branch IDT
acoustically coupled to the series IDT, and disposed on a transmission
path which branches from a transmission path between the input and output
terminals to a reference potential. Among the plurality of IDT's,
.lamda.a.gtoreq..lamda.b is established, where .lamda.a represents an
electrode finger pitch of the IDT to which the phase rotating element is
connected, and .lamda.b represents an electrode finger pitch of the IDT
to which no phase rotating element is connected.