The invention discloses an assist device for tooth extraction which mainly comprises a high frequency vibrating tool bit driven by ultrasonic wave. The tool bit accords with tooth anatomical morphology and has a front chiseling edge or/and a side scraping edge. This tool bit utilizes high frequency oscillation provided by an ultrasonic host to make the ultrasonic tool bit move back and forth at high speed[w1], thus to facilitate the cutting of periodontal ligaments by the tool bit and to loose teeth through high frequency oscillation.