To quickly reproduce the optimum treatment attitude and position after a stop in case of emergency by once stopping the operation in case of emergency while the setting operation for the working attitude and positioning is being made and restoring to the optimum treatment attitude and position by the restoring operation for the optimum attitude and position.
An operator turns manual switches 77-80 and sets the optimum treatment attitude and position for performing dental treatment. He pushes Auto-1 set switch 71 or Auto-2 set switch 72 while a memory switch 70 is held pushed so that the positioning of Auto-1 or Auto-2 as the fundamental attitude is set, and this is written in a memory 40. If an emergency situation is generated while the operation with the gurgle set position is being made from a gurgle set switch 74, an emergency stop button 76 is turned to stop the operation. Because the set position is stored at this time, restoration to the original position can be given at once when the next operation is to be restarted.