PURPOSE: To extend considerably the pot life of a magnetic paint by inactivating at least either of the hydroxyl group or isocyanate group of a curing type binder component by a specific material incorporated into the magnetic paint.

CONSTITUTION: The specific material is compounded with the magnetic paint and inactivates either the hydroxyl group or isocyanate group of the curing type binder component and when said material is dissolved in an org. solvent to be used for the paint, the material binds chemically with either group by, for example, addition effect such as solvation or chemical reaction. The material has the property to inactivate said group as well as to evaporate together with the org. solvent as the bond is stripped when the paint is coated on a synthetic resin base film and is then dried by heating. More specifically the curing reaction of the binder component is suppressed and since the increase in viscosity and the dispersibility are obviated, the pot life of the magnetic paint is remarkably extended.