Memory device and password storing method thereof

To provide a memory device and a password storing method thereof, according to which an improved security function is realized by resourcefully designing the storage position and/or storing order of password data stored in the memory device to prevent unauthorized password acquisition. The memory device makes a determination of whether or not rewriting and/or reading of data is permitted by verification of a password, the memory device comprising a plurality of partial memory areas which store a plurality of partial bit strings that comprise a bit string of the password, and wherein the plurality of partial memory areas are located apart from each other in a memory cell array.