AQUEOUS INK COMPOSITION FOR BALL-POINT PEN AND BALL-POINT PEN INCLUDING THE SAME

PROBLEM TO BE SOLVED: To provide an aqueous ink composition for ball-point pens which can suppress wear of a ball receiving seat due to rotation of a ball by imparting a high lubrication effect, secure good ink discharging properties throughout long-distance writing even when pigments are used as colorants, a possibly disadvantageous condition with respect to wear of the seat, or the composition is applied to extra-fine ball-point pens, and keep an excellent writing feeling comparable with the initial one for a long period.SOLUTION: The aqueous ink composition for ball-point pens comprises at least pigment carbon black, water and 5-methylbenzotriazole. A ball-point pen including the aqueous ink composition for ball-point pens and provided, at the writing tip, with a super-hard alloy ball using cobalt as a metal binder in a cobalt content of 1-20 mass% relative to the total amount of the ultra-hard alloy ball is also provided.