An air-oxidative type hair dye composition containing a melanin precursor prepared by a process including (A) an oxidation step for converting, into the melanin precursor, a tyrosine or derivative thereof used as a starting substance with an enzyme or cell that is derived from a fungus selected from the group consisting of fungi belonging to the genera Aspergillus, Neurospora, Rhizomucor, Trichoderma, and Penicillium and that exhibits a catechol oxidase activity.
