A film bulk acoustic resonator includes a substrate having a through hole which is defined by an opening on a bottom surface of the substrate opposed to a top surface thereof. A width of the opening is larger than that at the top surface. A bottom electrode is provided above the through hole and extended over the top surface. A piezoelectric film is disposed on the bottom electrode. A top electrode is disposed on the piezoelectric film so as to face the bottom electrode. A sealing plate is inserted from the bottom surface into the through hole so as to seal the opening.