The medical device system includes: first and second medical devices that are used in the body cavity and surfaces of which have conductivity a first electrode electrically connected to the surface of the first medical device a second electrode electrically connected to the surface of the second medical device a resistance measuring unit for measuring an inter-device resistance value between the first electrode and the second electrode a threshold storing unit for storing a predetermined lower limit threshold of the inter-device resistance value a determining unit for determining, when the inter-device resistance value is lower than the inter-device resistance threshold, that the first medical device and the second medical device come into contact with each other and a warning generating unit for generating a warning.
