A formulation of elastoplastic stress analysis of the laminated structure is shown on the basis of the finite element method using the assumptions of Voigt and Reuss. Systematic tests were carried out at room temperature with specimens composed of stainless steel and epoxy resin to depict a slip curve representing the interface strength. Three and four point bending tests were performed to verify the validity of the composite theory developed here. The data on the strength of separation were used in the numerical analyses. Comparison of the numerical results and experimental results are fairly good.