The deformation capacity of fractured member tends to have large dispersion, and it is difficult to verify the reliability and applicability of empirical knowledge. That is partly because the deformation capacity depends on the strain distribution in longitudinal direction as well as the fractured section's performance. In this study, the full-scale test results of previous researches were evaluated in terms of strain hardening level in order to investigate the fractured section's performance exclusively. As a result, it was confirmed that material toughness or current improved scallop was effective to prevent the deterioration of strain-hardening in fractured flanges. Without the deterioration, the approximate method provided satisfactory estimation of beam's deformation capacity.