It is well known that ductility of highly compressive pre-strained steel is inferior to that of unstrained steel. On the other hand, it has been found that the equivalent plastic strain to initiate ductile failure depends on the stress “triaxiality”. In this research, flat plate specimens, which were previously bent and pre-strained, were used in reversed bending tests and the conditions of ductile crack initiation was correlated with various compressive pre-strains. It is found that ductile cracks occur from the microscopic “wrinkles” which were formed on the concave surface of the bent specimen owing to the compression. Triaxiality-equivalent plastic strain history at the bottom of the wrinkle was obtained by FEM analysis, and compared with the limit curve of ductile crack initiation. FEM results were in good agreement with the test results and estimated the ductile crack initiation.