PROBLEM TO BE SOLVED: To obtain a quinacridone pigment economically profitably without causing environmental disruption by hydrolyzing a reaction mixture obtained by cyclizing a specified dianilinoterephthalic acid with a polyphosphoric acid or a polyphosphate. SOLUTION: A dianilinoterephthalic acid represented by formula I (R to R are each H, Cl, Br, F, a 1-4C alkyl, a 1-4C alkoxyl, a carboxamido, or a phenoxy or 6-18C aryl ring which may be fused with an aromatic, aliphatic or heterocyclic ring) is cyclized with 3-10 pts.wt., per pt.wt. the above terephathlic acid, polyphosphoric acid or polyphosphate at 80-150 deg.C for 0.5-24hr to obtain a reaction mixture. A pre-pigment obtained by hydrolyzing this mixture with water or an aqueous mineral acid solution at 110 deg.C or above under elevated pressure is heat-treated at 50-200 deg.C for 1-24hr to obtain a coarse crystalline crude pigment. The crude pigment is ground in an aqueous medium, an aqueous/organic medium or an organic solvent to obtain a quinacridone pigment represented by formula II.