PROBLEM TO BE SOLVED: To provide a medical observation system enabling its camera to be exchanged to a high-accuracy and high-performance one, enabling observation approach from a desired angle by giving enough medical treatment space to an operator to perform smooth movement, and enabling an endoscope to be easily attached/detached to/from an arm device.SOLUTION: A medical observation system 1 is selectively constructed in any one of a first system configuration and a second system configuration. The first system configuration includes: an arm part 3 and an observation part 2. The arm part 3 includes: a holding part provided with a link mechanism 7 and a swing mechanisms 25, 26 and a grip part 27 provided with a switch 28 for switching between a fixed state and a movable state. The observation part 2 includes: an endoscope 31 having a bent portion and a camera part 32 to be united/separated to/from the endoscope 31. Here, the endoscope 31 and the camera part 32 are mounted to the grip part 27. The second system configuration includes an observation part 2 in which the endoscope 31 and the camera part 2 are detached from the grip part 27 and the detached camera part 2 and the detached grip part 27 are united with each other.
