A multi-mode surface acoustic wave filter device includes: a piezoelectric
substrate; at least one input IDT (interdigital transducer) and at least
one output IDT that are formed on the piezoelectric substrate; reflectors
that are formed on the piezoelectric substrate and arranged on the
external sides of the input IDT and the output IDT; an input terminal
that supplies input signals to the input IDT; and an output terminal that
receives output signals from the output IDT. In this multi-mode surface
acoustic wave filter, the input terminal and the output terminal extend
in the same direction.