There is provided a piezoelectric resonant element having excellent electrical characteristics in which spurious is suppressed. The piezoelectric resonant element (10) is constituted by sticking a pair of oscillatory electrodes (12, 13), respectively, to both major surfaces of a rectangular piezoelectric substrate (11). In the nonopposing regions of both the oscillatory electrodes (12, 13), extending portions (12c, 13c) are provided to extend in the opposite directions outward from the center X of the opposing region.