To provide magnetic tape for use in a helical scan magnetic recording and reproduction unit that can maintain an excellent electromagnetic conversion property, running durability and running stability for a long period of time.

The magnetic recording medium is used in the helical scan magnetic recording and reproduction unit. A magnetic recording medium 10 has a magnetic layer formed on long non-magnetic supporting material using a vacuum thin film depositing technique, and diamond-like carbon protective layer formed on the magnetic layer. The magnetic recording medium 10 has a hardened area of the non-contact part 11 of the protective layer, where a magnetic head does not touch when the helical scan magnetic recording and reproduction unit is operated, for which plasma treatment is performed under an argon and nitrogen atmosphere.