To provide a highly crystalline polyketone having excellent heat stability, alkali resistance and acid resistance and excellent in stability of dope in an inorganic salt solvent and to provide a method for producing the highly crystalline polyketone.

The polyketone has an isopropyl group (terminal group A) in which at least one end is represented by chemical formula (1) and has 0.30-1.00 equivalent ratio of (terminal group A/total terminal groups).