To provide a surface mounted crystal oscillator whose electric connection is ensured by maintaining miniaturization.

In the surface mounted crystal oscillator having a container body 1 whose planar contour is made rectangular and whose cross section is made into the recessed shape having a metal ring 5 for welding on the aperture end surface, an IC chip 2 flip-chip bonded to the inner bottom surface of the container body 1, a holding substrate 9 with a pair of crystal holding terminals 10 fixed on the IC chip 2 and a crystal chip 3 electrically connected to the crystal holding terminals 10 of the holding substrate 9, it is constituted so that a pair of crystal connection terminals 11 are provided on the aperture end surface of one side of the container body 1 to be the inner peripheral side of the metal ring 5 and the crystal holding terminals 10 are connected with the crystal connection terminals 11 with conductive wires by wire bonding.