Provided are a memory device that undergoes no structural phase change, maintains a uniform thin film, and can perform a high-speed switching operation, and a method of operating the same. The memory device includes a substrate, an abrupt MIT material layer, and a plurality of electrodes. The abrupt MIT material layer is disposed on the substrate and undergoes an abrupt metal-insulator transition by an energy change between electrons. The plurality of electrodes are brought into contact with the abrupt MIT material layer and are melted by heat to form a conductive path on the abrupt MIT material layer.