PURPOSE: To suppress the adsorption of the chlorine-component in the atm. air to a thin ferromagnetic metallic film layer and to improve the corrosion resistance of said layer by providing a back coat layer contg. metallic soap having excellent hydrochloric acid capturing performance on the rear of a magnetic recording medium.

CONSTITUTION: The metallic soap used in the back coat layer is incorporated with good stability into the back coat layer and has low toxicity an excellent hydrochloric acid capturing property. If such kind of the metallic soap is incorporated into the back coat layer, the chlorine-component in the atm. air is preferentially adsorbed to the back coat layer contg. the metallic soap having the excellent hydrochloric acid capturing property by which the adsorption of the chlorine to the thin ferromagnetic metallic film layer is effectively suppressed and the corrosion resistance of the thin ferromagnetic metallic film layer is substantially improved. Since the metallic soap has a lubricating effect, the coefft. of friction of the back coat layer is decreased and the running stability of the magnetic recording medium is improved.