A phase change memory device includes a phase change resistor configured to sense a change in crystallization state due to current flow in order to store data that corresponds to the crystallization state. The phase change memory device is driven by reading cell data of a selected unit cell using a reference current. The cell data is compared to write data and then it is determined whether the write data is set data or reset data if the cell data is different from the write data. The set or reset state is written to the cell and verified during a write and verification operation under various conditions to stably write the data.