To provide an eraser-usable water-baser writing ink composition, which satisfies both of an erasability such that a hardwriting formed by writing on paper using the ink composition can be readily erased by an eraser and a writing maintenance property such that the handwriting cannot be eliminated by simply rubbing the paper with a finger or paper, and which also can have the handwriting fixed by heating, and a writing utensil having the ink composi tion built therein.

The eraser-usable water-base writing ink composition contains therein thermoplastic colored resin granules and tacky resin granules, wherein 70 wt.% or more of the respective granules are distributed in the range of 2-20 μm, or contains tacky colored resin granules and thermoplastic resin granules, wherein 70 wt.% or more of the respective granules contained and distributed in the range of 2-20 μm.