A magnetization apparatus includes a power supply unit, an energy storage element and a voltage clamp unit. The power supply unit generates at least one exciting signal to excite at least a coil of a magnetic field generating apparatus. The voltage clamp unit has a clamping voltage. The voltage level of the clamp voltage is higher than the voltage level of the exciting signal, and lower than the rated voltage of the energy storage element. When the exciting signal turns to a low voltage level, the voltage clamp unit controls the voltage level of the energy storage element to be less than or equal to the voltage level of the clamp voltage. This configuration with the voltage clamp unit can extend the lifetime of the energy storage element and reduce the energy loss to enhance the efficiency.