To provide a piezoelectric resonator in which a casing houses a tuning-fork piezoelectric resonator element and whose failure occurrence caused when shavings of adjustment films scatter and adhere to excitation electrodes is prevented. In a method of manufacturing a quartz-crystal resonator in which a casing 20 houses a quartz-crystal resonator element 10 including a tuning-fork quartz-crystal piece 11, excitation electrodes 6a, 6b, 6c, and adjustment films 8 for frequency adjustment, a wall surface 29 preventing shavings of the adjustment films 8 from scattering is formed between an atmosphere where the excitation electrodes 6a, 6b, 6c are located and an atmosphere where the adjustment films 8 are located inside the casing 20, and when the adjustment films 8 are shaved by a laser beam in order to adjust the frequency of the quartz-crystal resonator element 10, the wall surface 29 prevents the scattering shavings from adhering to the excitation electrodes 6a, 6b, 6c and causing a short circuit thereof, thereby reducing the occurrence of a failure.