Abstract: A submersible vessel includes: a hull; a propulsor that propels the hull; a front sensor that sequentially detects locations of an inspection target in front of the hull; a controller that controls the propulsor such that the hull passes through above the detected locations; a movable arm attached to an arm reference point of the hull; an inspection tool at the movable arm that inspects the inspection target; and a position detector that acquires positional information including a position, attitude, or speed of the hull. Based on the information from the position detector, the controller estimates a pass-through position of the arm reference point after a predetermined time. The controller controls the movable arm such that before the time elapses, a positional relation between the arm reference point and inspection tool becomes a positional relation between the estimated pass-through position and a target point on or above each location.