To provide a cost-saving surface mount crystal oscillator by making the amount of a fusion alloy constant at an outer circumferential part of a metal cover.

The crystal oscillator is provided with: a ceramic base to the outer circumference of which Au plating is applied and on which at least a crystal chip is mounted; and a metal cover which includes a first layer made of Ni, a second layer made of Au and an eutectic alloy part including Au provided onto the second layer at the outer circumference. The eutectic alloy is heated and fused to join the ceramic base with the metal cover. The Au of the second layer in the metal cover is provided only to the outer circumference.