PURPOSE: To provide the ultrasonic vibrator with excellent water tight performance with a support in which a metallic layer for an electrode is hardly exfoliated.

CONSTITUTION: A main electrode (1st metallic layer) 14 is formed to the front side of an insulation disk 11 made of an insulation material such as a ceramic and a sub electrode (2nd metallic layer) 18 and a lead wire connection land (3rd metallic layer) 16 connecting to a strip shaped prolonged metallic layer 15 prolonged in crossing with a disk circumference from the 1st metallic layer 14 are formed to a rear side of the insulation disk 11, in the ultrasonic vibrator, a strip metallic layer 15 is formed in a notch 12 formed to the insulation disk circumferential ridge so as to prevent the metallic layer from being projected to the insulation disk outer circumferential face thereby enhancing smooth mount to the support and the close contact property with the support.