Recently, cast-in-steel shell (CISS) pile has been used as the foundation of bridges and a pier is directly connected to the pile. In this case, plastic hinge is generally formed at the connection between the CISS pile and reinforced concrete pier. To increase the flexural capacity of such structure, a proper improvement method is necessary for the connection. In this study, a steel tube, a steel pipe that has 270mm diameter with 4.5mm thickness, has been used to enhance flexural capacity of the connection and the effect by the such method was evaluated through cyclic compression-bending test. From the test results, it can be found that the flexure capacity is considerably increased by applying the steel tube at the connection when it was compared to a general reinforced concrete (RC) pier with 10% larger diameter cross-section.