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.