This paper deals with robust control of magnetically suspended steel plates by using a switching control based on Generalized Internal Model Control (GIMC) structure. First, we derive a mathematical model for the magnetically suspended steel plate. The system is a multi-input and multi-output unstable mechatronic system. Then we design a robust controller which achieves both of high performance and high robustness for the magnetically suspended steel plates. GIMC structure is constructed with a general outer feedback loop and an inner loop. The outer-loop controller is a nominal high performance controller and it can be used for the nominal plant. On the other hand, the inner-loop controller is designed via the parameterization of a set of stabilizable controllers. Finally, several experimental results show that the GIMC structure based switching controller has both of high performance for the nominal plant and the high robustness for the perturbed plants compared with a μ controller.