Abstract: A magnetic head usable in a reader-writer for reading and writing data which can be magnetically processed. The magnetic head is characterized in that: it comprises a core (1), an exciting coil (2) for exciting the core (1), and a head case (3) for tightly enclosing the core (1) and the exciting coil (2); and a fuse is provided in a part of the exciting coil (2). When the reader-writer in which the magnetic head is incorporated is to be abandoned, the magnetic head can be easily destroyed, thereby enabling the prevention of fraudulent uses, such as the forging, of magnetic cards.