A pigment dispersing agent of the formula (1) capable of providing a printing ink or a coating composition excellent in fluidity and dispersion stability and a dry coating excellent in gloss, a pigment composition containing the same and a pigment dispersion containing the same, ##STR00001## wherein X.sub.1 is --NH--, --O--, --CONH--, --SO.sub.2NH--, --CH.sub.2NH--, --CH.sub.2NHCOCH.sub.2NH-- or --X.sub.3--Y--X.sub.4--, X.sub.2 and X.sub.4 are --NH-- or --O--, X.sub.3 is --CONH--, --SO.sub.2NH--, --CH.sub.2NH--, --NHCO-- or --NHSO.sub.2--, Y is an alkylene group, an alkenylene group or an arylene group, Z is --SO.sub.3M or --COOM, R.sub.1 is a heterocyclic ring residue or an aromatic ring residue, Q is --O--R.sub.2, --NH--R.sub.2, a halogen group, --X.sub.1--R.sub.1 or --X.sub.2--Y-Z, R.sub.2 is a hydrogen atom, an alkyl group or an alkenyl group, and M is one equivalent of a monovalent to trivalent cation.