Bonding-type surface-mount crystal oscillator

A crystal oscillator, comprising:

• a crystal unit having a container body in which a crystal blank is housed and hermetically sealed, said container body having external terminals at four corners of an outer bottom surface thereof;
• and
• a mounting substrate that houses an IC chip having at least an integrated oscillating circuit that uses said crystal unit, said mounting substrate having a recess for housing the IC chip, and said mounting substrate having bonding terminals corresponding to said external terminals at four corners of a top surface of the mounting substrate,
• wherein at least the external terminals of said crystal unit that are located at a pair of diagonal corners of the crystal unit are formed as protrusions from the outer bottom surface, and the bonding terminals corresponding to the external terminals formed as protrusions are disposed in depressions which are formed in the top surface of said mounting substrate separately from the recess to receive the external terminals formed as protrusions, and
• said mounting substrate is electrically and mechanically bonded to the outer bottom surface of said crystal unit by fitting said protrusions into said depressions and bonding said external terminals to the corresponding bonding terminals by soldering.