To provide a method for efficiently and safely producing a polyketone at a high yield per weight of a catalyst without deterioration in catalyst activity in polymerization.

The method for producing a polyketone comprises copolymerizing carbon monoxide with an ethylenically unsaturated compound using as a catalyst a metal complex composed of at least one compound (a) of a transition metal selected among groups 9, 10 and 11 and a ligand (c), where the copolymerization is carried out in the presence of a metal compound (b) capable of oxidizing the transition metal.