To provide a small boat in which a simple opening and closing valve is a drive device in place of a conventional propulsion device of a screw propeller.

A valve-driven boat comprises a hull and a propulsion device which is engaged with the hull in a reciprocation manner, and provided with a cylindrical body 1 which is advanced/retracted in a reciprocation manner with respect to the hull and submerged in water, a control valve 2 fixed in the cylindrical body approximately orthogonal to its axis. The ship has the propulsion device provided with the valve 2 to advance the boat by opening the valve 2 when the cylindrical body 1 is advanced, and moves the water in the cylindrical body 1 backward by closing the valve 2 when the cylindrical body is retracted, and a driving means reciprocates the cylindrical body 1 in an advancing/retracting manner. Only the valve can be driven by fixing the cylindrical body 1. The driving means can be manually or mechanically driven.