A piezoelectric device includes a base substrate constituting the bottom
of the package; a framed resonator element layered on the base substrate;
and a lid for hermetically sealing a space within the package, the lid
being layered on the framed resonator element. The framed resonator
element includes a frame constituting a wall surrounding the space within
the package; a base having a predetermined width, which is integrally
formed inside the frame; a plurality of resonating arms that extend in
parallel to each other from the base in one direction in the frame; first
cutouts that are provided near the base ends of the resonating arms in
the base; and second cutouts formed at the joint between the base and the
frame.