Abstract: A corrosion-resistant, quick disconnecting coupling assembly for piping use consisting of a female coupling and a male coupling for causing or stopping the conduction of a fluid by connection or disconnection between both is provided. The female coupling and the male coupling comprise each an exterior coupling body, a cylindrical valve member mounted in the body so as to form an annular closed chamber enclosed by the former two, which member has therethrough communicating transverse and longitudinal holes as a flow path of the fluid and a spring housed in the chamber so as to be compressible or extensible. The valve member is wholly or partially slidable. The one valve member may consist of a fixed valve and a slidable valve sleeve and the other valve member may be a slidable poppet valve. Each of the valve members may be a poppet valve which is slidable.