the present invention provides an aqueous pigment ink for ball - point pen which can inhibit surface tension from extremely deteriorating to protect written letters from blur and which is excellent in non - drying properties and which has lubricating properties enough to smoothly rotate a ball and to decrease friction of a ball seat , whereby a writing performance can be remarkably improved and a comfortable writing performance can be given . the aqueous pigment ink composition for ball - point pens of the present invention is characterized by comprising a pigment , a dispersant , water and an adduct of at least one polyhydric alcohol with an alkylene oxide , the polyhydric alcohol being selected from the group consisting of polyglycerin , glycerin , trimethylolpropane and a mixture thereof .