The aim of this paper is to propose new automatic mesh generator for the finite element analysis of threedimensional structures consisted of plates and beams. The strategy of the proposed one is as followings; Firstly, subdivide the structure into two-dimensional and one-dimensional structural components. Secondly, generate mesh pattern for each of them, and finally combine them so that they reconstruct the original configuration. By using the proposed method the modeling of, for example, steel bridge structures for Finite Element Analysis is easily and also fastly completed. Some examples of the application of the proposed method are presented, and from the examination of the results further important informations for the design of better method are also given in this paper.