Deformaion capacity of exposed column-base depends on elongation properties of the anchor bolts. The anchor bolt is consist of shank and thread. Shank of the bolt does yield when area ratio of thread to shank is lower than yield ratio. The thread of the bolt yields and short thread may break early under a severe earthquake. Then AIJ provision recommended that area ratio of thred to shank is larger than yield ratio and the shank yields before the thread reaches to its maximum tensile strength. However, it is possible to serve enough deformation capacity of the exposed column-base when thread length ratio set a proper value to a severe earthquake response. Heuce, we performed cyclic loading test on exposed column-base to show the possibility. We investigated the mechanical properties of the column-base by comparing the simple evaluation formula and F.E.M. analysis results. The results showed the F.E.M. analysis has good accuracy with experimental results and the required deformation capacity of the column-base could satisfied by adjusiting the thread length property.