A filter includes piezoelectric thin-film resonators having a substrate, a lower electrode supported by the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film. At least one of the piezoelectric thin-film resonators has a portion in which the upper electrode overlaps the lower electrode across the piezoelectric film. The above portion has a shape different from shapes of corresponding portions of other piezoelectric thin-film resonators, so that a spurious component in the above at least one of the piezoelectric thin-film resonators occur at a frequency different from frequencies of spurious components that occur in the other piezoelectric thin-film resonators.