The present invention relates to an anti-rotation structure for use in a handle of an ultrasonic dental scaler, the anti-rotation structure comprising a transducer, a rear clamping ring, and a handle casing. The rear clamping ring sleeves a main rod of the transducer, and is clamped with the main rod； and the clamping fit between the rear clamping ring and the main rod is used to prevent relative rotation between the rear clamping ring and the main rod. The handle casing sleeves the rear clamping ring； the rear clamping ring is clamped with the handle casing； and the clamping fit between the rear clamping ring and the handle casing is used to prevent relative rotation between the rear clamping ring and the handle casing. The beneficial effects of the present invention lie in the followings. After the adopted anti-rotation structure is packaged, the comfort of the handle can be effectively improved, the power is larger, and the torque transmission is more reliable.
