PURPOSE: The titled erasing solution, prepared by dissolving an acid in a mixed solvent of water with another polar solvent, and capable of easily erasing an ink consisting of a vehicle containing a resin soluble in a polar solvent other than water and a dye, etc. soluble in the vehicle and water to be colorless with certainty.

CONSTITUTION: An ink erasing solution prepared by dissolving an acid, e.g. preferably citric acid, in a mixed solvent of water with a polar solvent, e.g. methanol or ethylene glycol monomethyl ether, other than water, and capable of erasing an ink consisting of a vehicle containing a resin, e.g. a ketonic resin or rosin-modified phenolic resin, soluble in a polar solvent other than water, dissolved therein and a coloring component such as a dye, e.g. triphenylmethane dye, or acid-base indicator, e.g. phthalein, compatible with the vehicle and water and becoming colorless under acidic conditions, into a colorless state.

EFFECT: Capable of being written even on a nonabsorbing surface, and repeatedly written just after the erasing. No substance toxic to the human body is used therein.