To provide a boat capable of running by itself irrespective of the weather, where in a conventional self-propelled boat, it is difficult to run by itself when natural forces cannot be used such as waves or wind.

The boat comprises a bow portion carrying a person, a float portion undertaking buoyancy from the midship to a stern, an anchor portion for constantly sinking the stern underwater, and a fin portion generating propulsion by vertical movement of the boat. In a state of a stern portion constantly sunk underwater, the person rides in a position near a bow to provide balance, seesaw movement is caused by changing a load applied point of the person to a bow direction or a stern direction, a fin attached to the stern generates thrust by vertical movement of the stern sunk underwater, and the boat runs by itself.