To execute all the operations in a medical/dental treatment system easily with a foot by providing an electric switch for foot operation, display picture switcher for a display device, pointing device for foot operation, and foot manipulator equipped with an executing means for a selected picture mode.

An operator performs operating while placing the foot on a foot manipulator 17 but the front part of the foot is placed on a front pedal stand 11, and a mode changeover switch 12 is operated while vertically moving the toe. Concerning the selecting instruction of a position on a display screen, the intersection of X and Y axes is found by vertically and horizontally moving a pedal 5 of the foot manipulator 17. Namely, the X axis is selected by moving the pedal 5 in a horizontal moving direction 10 and the Y axis is selected by vertically moving the pedal 5. When performing click, after it is confirmed a marker is moved into the block of a required item on the screen, the toe is moved forward and a hole 13 for click is closed with the sole so that a signal can be used with the changes of a click light emitter and a click light receiver.