To reduce the outside dimension of a piezoelectric vibrator by cutting the part of a welding ring that swelled out of a surface mounting holder base after a cover and the welding ring are welded by resistance or contacted by bonding to each in the sealing process of the vibrator.

The projection of a welding ring is located at the inside of the fringe part of a surface mounting holder base. The holder base is positioned on a lower electrode and then a cover and a lower electrode are welded to the holder base by pressing them down. Then the projection of the welding ring and the cover are welded by resistance or contacted by bonding to each other. Thus, the inside of the holder base is sealed airtight. Then the part of the welding ring that swelled out of the fringe part of the holder base is cut by a metal cutter 9 or a laser after a lower holder 10 is placed under the holder base. As a result, the outside dimension accuracy of a piezoelectric vibrator is improved regardless of slippage of the cover or the dimension of the welding ring.