An electron beam curing resin for a magnetic recording medium is provided, wherein a known thermosetting vinyl chloride resin or polyurethane resin is modified to become sensitive to an electron beam, and the resulting resin has a high cross-linking property. A method for readily manufacturing the above-described electron beam curing resin from a known thermosetting resin is provided. Furthermore, a high-performance magnetic recording medium including the above-described electron beam curing resin is provided. The electron beam curing resin is produced through a reaction between active hydrogen groups of a vinyl chloride resin or polyurethane resin having the active hydrogen groups in a molecule and a compound having an isocyanate group and a radical-polymerizing unsaturated double bond in a molecule, wherein the amount of water in the reaction system is controlled at 0.05 to 0.5 percent by mass relative to the resin when the reaction is effected.