A piezoelectric device includes first and second piezoelectric resonators each including a piezoelectric thin film, an upper electrode provided on one main surface of the piezoelectric thin film, and a lower electrode provided on another main surface of the piezoelectric thin film. In the piezoelectric resonators, portions in which the upper and lower electrodes are superposed on each other with the piezoelectric thin film therebetween define piezoelectric vibrating portions that are acoustically isolated from a substrate. The first and second piezoelectric resonators are connected in series or parallel between an input terminal and an output terminal such that polarization directions of corresponding portions of the piezoelectric thin film are opposite to each other when seen from the input terminal. The first piezoelectric resonator and the second piezoelectric resonator are arranged to have different resonant frequencies of a transverse vibration mode.