Example embodiments may provide data storage devices using movement of a magnetic domain wall and/or a method of operating magnetic domain data storage devices. The data storage device may include a first magnetic layer for writing data having two magnetic domains magnetized in different directions, a second magnetic layer for storing data at a side of the first magnetic layer, a data recording device connected to the first magnetic layer and the second magnetic layer, and a plurality of reading heads configured to read the second magnetic layer. The data storage device may store a larger amount of data without requiring moving mechanical systems.