Ball valve

The invention provides a ball valve. The ball valve prevents contact of a ball body and a compression ring in a condition that a ball base is not arranged between a ball body and a compression ring and has excellent durability. The ball valve comprises a valve body with an input flow path, an output flow path and an inner space combined the flow paths, a ball body arranged in the inner space and opening and closing the flow paths through rotation along a reference axis, an operation mechanism driving the ball body to rotate along the reference axis, a valve rod used for combining the operation mechanism and the ball body, a ball base arranged in the inner space in a manner of surrounding the ball body and with an approximately cylindrical opening section in the side surface, a compression ring embedded at the opening section of the ball base. The compression ring has a protruding section protruding outwards from the peripheral end part at the end part of the valve body side. The ball base has a grooving secti