A nonvolatile memory device that utilizes both a voltage provided outside the memory device and a voltage generated within the device instead of using only a voltage generated within the device as a driving voltage avoids malfunctions of the memory device when instantaneous significant voltage drops occur. The nonvolatile memory device includes a plurality of nonvolatile memory cells, a bit line coupled to at least a portion of the plurality of nonvolatile memory cells, a column-selection transistor coupled to the bit line and a driving circuit. The driving circuit is coupled to a gate of the column-selection transistor and is configured to supply a charge to the gate using a first voltage and a second voltage wherein the second voltage is higher than the first voltage.