A surgical system includes: a medical device； a measuring portion that measures a three-dimensional position of an organ in the interior of a body cavity； a setting portion that sets, on the basis of the three-dimensional position of the organ, a non-interference region, which is a space in the interior of the body cavity excluding the organ； a detecting portion that detects a three-dimensional position of the medical device in the interior of the body cavity； a calculating portion that calculates, on the basis of the three-dimensional position of the medical device, a medical-device occupying region of the medical device in the interior of the body cavity； a predicting portion that predicts interference between the medical device and the organ on the basis of the positional relationship between the non-interference region and the medical-device occupying region； and an alerting portion that alerts an operator when interference is predicted.
