A piezoelectric thin-film resonator and a method of manufacturing thereof eliminate and prevent breaking of a piezoelectric thin film, disconnection of electrodes, and other known problems. The piezoelectric thin-film resonator includes a substrate and a suspended portion including a vibrating portion in which a piezoelectric thin film is disposed between a pair of excitation electrodes. At least two film-like supports partially supported on the substrate are provided. The suspended portion is supported by the supports so as to be suspended above the substrate with an air-gap layer therebetween.