A magenta ink composition used as a colorant, containing at least one type of compound represented by Formula (I) below and at least one type of compound represented by Formula (II) below: (wherein A represents the residue of the five member heterocyclic diazo moiety A-NH.sub.2; B.sup.1 and B.sup.2 represent --CR.sup.1.dbd. and --CR.sup.2.dbd., or one represents a nitrogen atom, and the other represents --CR.sup.1.dbd. or --CR.sup.2.dbd.; R.sup.5 and R.sup.6 each independently represents a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxy carbonyl group, aryloxy carbonyl group, carbamoyl group, alkyl sulfonyl group, aryl sulfonyl group, or sulfamoyl group, each group therein being optionally substituted; G, R.sup.1 and R.sup.2 each independently represents a hydrogen atom, halogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxy carbonyl group, acyl group, hydroxyl group, alkoxy group, aryloxy group, silyloxy group, acyloxy group, carbamoyloxy group, heterooxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group substituted with an alkyl group or aryl group or heterocyclic group, acylamino group, ureide group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkyl and aryl sulphonylamino group, aryloxycarbonylamino group, nitro group, alkyl and aryl thio group, alkyl and aryl sulfonyl group, alkyl and aryl sulfinyl group, sulfamoyl group, sulfo group, or heterothio group, each group therein being optionally substituted; and R.sup.1 and R.sup.5, or R.sup.1 and R.sup.5 may optionally bond together to form a 5 or 6 member ring); (wherein M represents a hydrogen atom, ammonium group, or alkali metal atom; X represents a diaminoalkylene group; and n represents either 1 or 2).