Apprentice dentists and dental hygienists must be trained "tooth scaling". However most of training schools have several problems, lack of cooperative patients with calculi, a great variety of calculi. The authors have developed a simulator for the training by using a PHANToM and a video-see-through HMD in the previous paper. In this paper, visual display of the simulator is improved in streoscopic. Then the training effectiveness has been evaluated based on difference between operation force by veterans and that by beginners. The result shows the developed simulator is effective, and the teaching function of the simulator contributes to training effect, whereas the stereo vision without the teaching function doesn't contribute so much.