An orthodontics assisting system includes index members which indicate respective reference positions of a pre-correction dentition model and a post-correction predictive dentition model an arranging device for arranging the index members an image data generating device for generating image data by imaging the pre-correction dentition model and the post-correction predictive dentition model a screen display for screen-displaying a pre-correction dentition image an a post-correction predictive dentition image respectively based on the image data, a position adjusting device for adjusting mutual display positions of the pre-correction dentition image and the post-correction predictive dentition image and a tooth position adjusting device for adjusting the display position of a teeth image.