There is provided a medical device system 1 that can detect, at an early stage, contact between medical devices 21 and 22 used in a body cavity and prevent breakage and the like of the medical devices. The medical device system 1 includes: first and second medical devices 21 and 22 that are used in the body cavity and surfaces of which have conductivity a first electrode 21E electrically connected to the surface of the first medical device a second electrode 22E electrically connected to the surface of the second medical device a resistance measuring unit 37 for measuring an inter-device resistance value between the first electrode 21E and the second electrode 22E a threshold storing unit 36 for storing a lower limit threshold of the inter-device resistance value a determining unit 34 for determining, when the inter-device resistance value is lower than the inter-device resistance threshold, that the first medical device 21 and the second medical device 22 come into contact with each other and a warning generating unit 35 for generating a warning.
