A medical device system includes a first medical device, a first memory corresponding to the first medical device, a second medical device, and a second memory corresponding to the second medical device, wherein the first medical device includes a first writing unit that dynamically writes, into an area included in the first memory, definition data that defines a method for using the area and data corresponding to the definition data, and the second medical device includes a second writing unit that dynamically writes, into an area included in the second memory, definition data that defines a method for using the area and data corresponding to the definition data.
