A method of purifying a pigment dispersion including: bringing an unpurified pigment dispersion containing a pigment and impurities into liquid-liquid interfacial contact with an extracting liquid in a microspace, and extracting and removing the impurities in the unpurified pigment dispersion into the extracting liquid to obtain a purified pigment dispersion. Further, an apparatus for purifying a pigment dispersion, a pigment dispersion and an ink set using the same, and a droplet-ejecting apparatus and an inkjet-recording ink tank using ink prepared by employing the pigment dispersion are provided.