Patent ID: 7876029

Claim:
A piezoelectric device, comprising: a piezoelectric resonator element; a package storing the piezoelectric resonator element therein in a manner to mount the piezoelectric resonator element on a base portion thereof composed of at least three layers that are layered; and a through hole penetrating through the base portion, wherein the through hole includes: a first hole formed on a first layer that is positioned to face the piezoelectric resonator element among the at least three layers; a second hole formed on a second layer contacting with the first layer; a third hole formed larger than the second hole, on a third layer contacting with the second layer; and a metal coat formed on an inner wall surface of the second hole, and a sealing part for sealing the package is formed with a sealant in at least the second hole, wherein the metal coat is extended on an exposed surface of the second layer, the exposed surface being exposed inside the third hole.