An improvement of a magnetic recording medium in the continuous form comprising a nonmagnetic support, a magnetic recording layer provided on one surface of the support, and a back layer provided on the other surface of the support comprising a binder and nonmagnetic particles dispersed therein. The improvement resides in that the binder of the back layer mainly contains:a polyurethane resin containing a repeating unit having at least one polar group selected from the group consisting of --SO.sub.3 M, --OSO.sub.3 M, --COOM and --PO(PM').sub.2, wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group; anda vinyl chloride copolymer containing a repeating unit having at least one polar group selected from the group consisting of --SO.sub.3 M, --OSO.sub.3 M, --COOM and --PO(OM').sub.2, wherein M and M' have the same meanings as defined above.