A surgical system (100) includes: a medical device (1) an organ measuring means (7) for measuring a three-dimensional position of an organ (D) in the interior of a body cavity a non-interference-region setting portion (10) that sets, on the basis of the three-dimensional position of the organ (D), a non-interference region, which is a space in the interior of the body cavity excluding the organ (D) a medical-device detecting means (8) for detecting a three-dimensional position of the medical device (1) in the interior of the body cavity a medical-device-occupying-region calculating portion (11) that calculates, on the basis of the three-dimensional position of the medical device (1), a medical-device occupying region of the medical device (1) in the interior of the body cavity an interference predicting portion (12) that predicts interference between the medical device (1) and the organ (D) on the basis of the positional relationship between the non-interference region and the medical-device occupying region and an alerting portion (13) that alerts an operator when interference is predicted by the interference predicting portion (12).
