A band-pass filter device includes: a plurality of band-pass filter
elements on a principal plane of a substrate; wherein the band-pass
filter elements correspond to a plurality of respective channels divided
by frequency regions, and each have a plurality of piezoelectric
resonators. Each of the piezoelectric resonators includes a piezoelectric
film whose periphery is supported by the substrate, a first electrode
formed on a lower surface of the piezoelectric film, a second electrode
formed on an upper surface of the piezoelectric film and formed in a
state of overlapping at least a part of the first electrode with the
piezoelectric film interposed between the second electrode and the first
electrode, a lower space formed between the substrate and the
piezoelectric film, and an upper space formed over the piezoelectric
film.