PURPOSE: A writing utensil, prepared by the combination of a anhydrous ink containing a water-soluble coloring component and a vehicle without water as a writing part and an erasing solution obtained by dissolving an acid which is a decoloring component in a mixed solvent of water with a polar solvent other than the water as an erasing part, and easily erasable with certainty.

CONSTITUTION: A writing utensil obtained by the combination of a writing part containing an ink consisting of a vehicle containing a resin, e.g. a ketonic resin, soluble in a polar solvent, e.g. methanol or ethylene glycol monomethyl ether, and a coloring component consisting of a dye, e.g. triphenylmethane dye, or acid-base indicator, e.g. phthalein, compatible with the vehicle and water, and capable of being colorless under acidic conditions and an erasing solution prepared by dissolving an acid, preferably citric acid, as a decoloring component in a mixed solvent consisting of water and a polar solvent other than the water.

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.