It was confirmed that many urban viaduct were damaged around bearings by Hyogoken Nanbu Earthquake. In case of bearing supports were damaged heavily, it was indicated that secondary damages were occurred by the collision of upper structure with lower structure. However, a modeling of bearing support is difficult for seismic response analysis because studies about seismic capacity of bearing supports are not enough yet. Therefore, it is necessary to clear the process of fracture of bearing support during strong earthquake. In this paper, we proved the process of fracture of pin type bearing supports by the experimental approach.