In a crystal oscillator accordance to an embodiment, a crystal resonator plate is bonded to, via laminated bonding patterns, a first sealing member covering a first excitation electrode of the crystal resonator plate; and a second sealing member covering a second excitation electrode of the crystal resonator plate. An internal space is formed, which hermetically seals a vibrating part including the first and second excitation electrodes of the crystal resonator plate. The laminated bonding patterns include a laminated sealing pattern annularly formed to surround the vibrating part in plan view so as to hermetically seal the internal space, and a laminated conductive pattern establishing conduction between wiring and electrodes. The laminated conductive pattern is disposed within a closed space surrounded by the laminated sealing pattern. To the laminated sealing pattern, GND potential is applied when the crystal oscillator operates.