Abstract: A cable detecting system with a cable ship, a cable detector towed by said cable ship via a towing wire and said cable detector dredging the water bottom to find a buried cable, has been improved. When the cable detector detects a buried cable, and the cable is engaged with the cable detector, the towing wire between the cable ship and the cable detector is released either by drawing out a wire from the cable ship or by extending an auxiliary wire from the cable detector, thus, the cable detector stops just when a cable is detected, even when the cable ship continues to move by inertia, and no damage is caused to the cable. The presence of a cable is sensed either through a mechanical means which detects the cable by contact between the cable and the detector, or through electromagnetic means. The detection of a cable triggers the above release of the towing wire.