The superconducting magnetic levitation vehicle system (Maglev) is being developed. In the guideway steel structures, the energy loss and the resistance to the movement of vehicle, called a magnetic drag force, are induced by the passage of vehicle. It is very important to evaluate the magnitude of the drag force quantitatively and to make it small below the limit value when we use the steel as a member of guideway structure. In the accordance with magnetic drag force, the approximate analysis method is proposed, and also the characteristics and the reducing measures are investigated by our experiments and the analysis.