The present invention relates to a two-level mounting board in which a second substrate is supported horizontally by a metal pin above a first substrate having a mounting electrode on an outer base surface, the free, lower end of the metal pin is inserted in a hole provided in the surface of the first substrate, and the metal pin is affixed by solder to an annular electrode land provided on the surface of the first substrate to form an outer periphery of the hole, wherein part of the ring of the annular electrode land is cut away to open the same. This provides a two-level mounting board in which metal pins can be connected reliably to the first substrate to support the second substrate horizontally, and a crystal oscillator using the same.