Provided are partially and fully earth-anchored cable-stayed bridges, each of which uses a prestressing unit including anchor units and a prestressing member from deck segments installed at its main span such that the prestressing unit serves as a conventional windproof cable and can simultaneously introduce a tensile stress. Thereby, a magnitude of the maximum compressive stress acting on a cross section of each main-span deck segment is reduced, so that it is possible to reduce a cross-sectional area of each main-span deck segment and thus to ensure economical construction. All or part of the compressive stress generated at the main span can be offset by the tensile stress caused by the prestressing member.