A nonvolatile memory device comprises a plate line driving circuit having a hierarchical word line structure. The plate line driving circuit is coupled to plate lines corresponding to a main word line. The plate line driving circuit transmits a plate line drive signal to the plate lines when the main word line is selected, and connects the plate lines to the main word line when the main word line is unselected. Therefore, a floating condition in the plate lines when the main word line is unselected can be prevented.