To provide a method for manufacturing a high molecular weight polyketone useful as an industrial material in a high yield and for a short time and at a low cost.

The method for manufacturing the polyketone from carbon monoxide and an ethylen unsaturated compound, comprises polymerization under a specific pressure and temperature, using a metal complex catalyst which is obtained from a palladium compound, a bidentate ligand having an atom of a group 15 element of the periodic table and an anion from an acid having a pKa of 4 or less, in a liquid medium which consists of a water soluble organic solvent and water and besides has such a water content of 1-50% as is expressed by equation (1): water content (%)={(a mass of water)/[a volume of whole water soluble organic solvents (ml) + a volume of water (ml)]}×100.