A medical system includes an operation panel provided with an LCD touch panel and an ultrasound observation apparatus connected via a cable. When a comment receiving section of the operation panel receives comment information from a comment transmitting section of the ultrasound observation apparatus, an LCD image processing section changes a comment on the LCD touch panel according to the comment information, an operation control section sends out information about the change to an apparatus control section, and the ultrasound observation apparatus changes a comment display of a predetermined portion on a diagnosis monitor.