There are provided a surface-mounted crystal oscillator and a manufacturing method thereof which can realize miniaturization, improve quality, reduce a manufacturing cost, and enhance productivity. According to the surface-mounted crystal oscillator and the manufacturing method thereof, through terminals and of AgPd are formed on wall surfaces of through holes formed at corner portions of a rectangular ceramic substrate, a metal electrode of a support electrode lower portion of AgPd which is connected to the through terminal and forms a lower layer of a support electrode is formed on a front side of the substrate, the support electrode which holds a crystal piece is formed on the support electrode lower layer portion by using Ag, and a cover is mounted on an insulating film formed on the inner side of the periphery of the substrate and effect airtight sealing.