PURPOSE: To improve stability and SN ratio, by coating a base with a magnetic coating material contg. an acrylic oligomer, a specified vinyl type copolymer, etc. as a binder, and a magnetic iron powder dispersed into the binder, and hardening it by irradiation of radiation.

CONSTITUTION: A magnetic coating material is prepared by dissolving or dispersing 80pts.wt. magnetic iron powder; 10pts.wt. radiation-polymerizable acrylic oligomer; 10pts.wt. e.g., butyral resin, selected from vinyl chloride type copolymers; and 1pt.wt. palmitic acid in 160pts.wt. solvent mixture of toluene and ketone. The butyral resin as the binder is stable against radiation, and the acrylic oligomer is cross-linked and hardened by radiation. A polyester film base is coated with this coating material, dried, and hardened by irradiation of radiation to obtain a magnetic tape, serviceable as a magnetic recording medium improved in stability and SN ratio.