Provided is an aqueous ink composition for a writing instrument which is excellent in a drying property of the drawn lines and a low temperature stability of the ink while inhibiting the pen tip from drying and which prevents the drawn lines from causing feathering and strike-through. The aqueous ink composition for a writing instrument described above contains at least a colorant, trimethylglycine, pentaerythritol, 10 % by mass or less of a water-soluble organic solvent, and water.
