To obtain an ink composition capable of providing clear images of suppressed blur even in the case of printing on plain papers, by including a coloring agent comprising particles having electric charge and a specific resin emulsion in an aqueous medium.

This ink composition is obtained by including (B) a coloring agent comprising particles having electric charge and (c) a resin emulsion having the electric charge with the identical polarity to that of the component B, in (A) an aqueous medium. Preferably, the component B comprises pigment particles each having a particle diameter of 50-200 nm, in particular, comprises carbon black having functional group. The component C is desirable to be such one as to contain a thermoplastic resin with a glass-transition temperature of ≥35°C and a minimum temperature for film formation of ≤20°C. The component C is pref. such one as to be selected from an acrylic resin emulsion, a vinyl acetate-based rein emulsion, vinyl chloride-based resin emulsion, styrene- acrylic resin emulsion, and styrene-based resin emulsion.