To provide a method for dyeing keratin fibers so as to exhibit good coloring ability and fastness wherein a reducing agent used does not delay dye absorption into the keratin fibers.

This method for dyeing keratin fibers comprises the following practice: a dyeing composition A where an oxidative dye and 0.1-15 wt.%, based on the whole composition, of ketose as reducing agent are contained in a medium suitable for dyeing is applied to keratin fibers, and laccase as oxidizing agent is used to effect color development of the keratin fibers in the presence of air in an alkaline, neutral or acidic medium. The laccase is put into either in the composition A or in a composition B; in the case of the latter, the composition A and the composition B are either mixed together just before use, or applied alternately to the keratin fibers.