PURPOSE: To increase the stability and to make accurate the oscillation, by sealing the crystal body and gas adsorbent in a package via an intermittent part.

CONSTITUTION: In a package formed with a cover 2 welded in airtightness at the external flange of a base 1, a crystal body 4 and gas adsorbent 6 are connected and supported with electrodes 7, 7' and 8, 8'. Between the crystal body 4 and the adsorvent 6, a shutter plate 9 is mounted on the base 1 in airtightness with a leg 10. The adsorent 6 adsobvs the gas produced in the package and at airtight sealing of a vent tube 3 to always keep clean the inside of the package. A lot of gas and particles are discharged from the adsorbent 6 in this case. The shutter plate 9 prevents the gas and particles from being stuck to the crystal body 4 for the change in the resonant frequency of crystal oscillator.