A bulk acoustic wave resonator includes a substrate, a resonator section in which a piezoelectric film is sandwiched between a pair of electrodes, and a vibration region where the electrodes overlap when viewed in a film thickness direction is defined, an elastically deformable support section that connects the substrate and the resonator section, a membrane arranged between the resonator section and the substrate to face the vibration region of the resonator section and be fixed on the substrate with a space in between, and driver sections that are defined in the resonator section and the substrate adjacent to the vibration region and the membrane, and that move the resonator section toward and away from the substrate. The vibration region of the resonator section contacts the membrane when the driver sections move the resonator section close to the substrate.