There is provided a water-base ink composition which has excellent ejection stability and can be evenly printed on recording media. The water-base ink composition comprises at least: a colorant component selected from dyes and pigments; a monovalent or divalent branched alcohol with C5 to C10 chain length; an acetylene glycol surfactant and/or a penetrating organic solvent; a humectant; and water. The monovalent or divalent branched alcohol with C5 to C10 chain length, the acetylene glycol surfactant and/or the penetrating organic solvent, and the humectant are selected from combinations of branched alcohols, acetylene glycol surfactants and/or penetrating organic solvents, and humectants which are miscible with one another.