PURPOSE: To enable painless cutting of teeth and tusks by bringing into contact with the outer circumferential surface of a tool and the like of a dental turbine and driving an output terminal of an ultrasonic oscillator for carrying out straight line oscillation so as to excite rotation and flexural oscillation on the tool to carry out oscillation cutting and oscillation grinding.

CONSTITUTION: An ultrasonic oscillator 1 for generating oscillation has two half-circular electrostrictive elements 2 and 3 which are divided half into upper and lower parts. These electrostrictive elements 2 and 3 are sandwiched by a metal material 7 whose diameter is changed so as to enlarge output amplitude and the other metal material 8 and firmly fastened with a center bolt 9. Half- circular electrode plates 4 and 5 are inserted between the elements of the electrostrictive elements 2 and 3, and an earth side electrode plate 6 is inserted between one of the electrostrictive elements 2 and 3 and the metal material 8. Therefore, a tool 11 which is rotatably supported is rotated by a frictional force of a tangential oscillation component and a radial oscillation component of a straight line oscillation of the ultrasonic oscillator 1, and a flexural oscillation is excited by the radial oscillation component to give an ultrasonic oscillation to a cutting edge.