This paper investigates the vibration of one-degree-of-freedom magnetically levitated body. Especially, the influences of the nonlinearity of the system and the dynamical characteristics of electric circuit and magnetic circuit are focused. This paper's object is extended to the case that electric current supplied from a power-operational amplifier is limited in a positive range. Thus, the system may have piecewise nonlinearity when the vibration amplitude is large. The nonlinear analysis for this system is discussed. The dynamical characteristics of the system are clarified by numerical simulation and theoretical analysis. These obtained results are confirmed by experiment.