The Rigid Bodies-Spring Models (as abbreviated RBSM) proposed by Kawai in order to generalize the well-known method of plastic analysis from a viewpoint of the discrete analysis have been applid to various types of nonlinear structural problems and their validities have been sufficiently demonstrated. It is a great contrast to the conventional finite element method that these discrete elements were developed for the main purpose of evaluating the ultimate strength of structures, so that the structural analysis by using the RBSM may be called the Discrete Limit Analysis. The physical concepts of the RBSM were definitely explained by Kawai in his literatures, but the algorithms for the application of the RBSM to arbitrary thin-walled structures were not necessarily obvious. Recently one of authors Toi has carried out the formulation of a series of rigid element models for shell structures and established the analytical procedure for these structures including arbitrary shells. In this paper the general formulation of curved rigid element models is carried out for the discrete limit analysis of shell structures whose middle surfaces are defined as the coordinate surfaces of the orthogonal curvilinear coordinate systems, following the physical concepts of the RBSM for the plate bending and plane strain problems. This general formulation is applied to circular cylindrical shells and some numerical results are shown. The present analytical procedure for circular cylindrical shells may be considered as the extension of the generalized yield line method developed by Sawczuk and Janas from the standpoint of the discrete analysis.