This paper describes the improvement of dynamics for a passive type superconducting magnetic bearing (SMB) system. The SMB system is composed of a pair of SMB's with high Tc (critical temperature) superconductors, and a rotor with some permanent magnets. The rotor is passively supported by the SMB's without any control mechanism. The superconductors of the SMB's were field-cooled in the experiments. After the superconductors were cooled, the bearing housings of the SMB's were forced to change in the axial direction. Then, the stiffness change and damping coefficient change resulting from the housing displacements were investigated. From the experimental results, it is found that the static stiffness is related to the dynamic stiffness, and that the stiffness and the coefficient change according to the housing displacements. The rotor displacement and the rotation angle near the resonance rotation speeds also change according to the housing displacements. These results show that the stifiness and the damping coefficient of the SMB system can be adjusted using the housing displacements.