PURPOSE: To obtain an agent for dyeing white hair containing iron salt, color former and cationic resin, having low skin stimulating property and exhibiting excellent hair dyeing property and hair fixing property.

CONSTITUTION: (a) Iron salt is blended with (b) one or two or more kind of substances selected from pyrogallol, tannic acid, gallic acid and hematin and capable of reacting with iron ion to develop into black and (c) cationic resin to provide the aimed product in production by ordinary method. The blend is carried out at amounts of 0.1W5.0wt.% iron salt, 0.1W10.0wt.% color former, 0.1W10wt.% cationic resin (as pure content) based on total amount of hair dyeing agent. As the iron salt and cationic resin, iron (II) sulfate or iron (II) chloride and homopolymer of dialkyldiallyl ammonium chloride are exemplified, respectively. Though the agent can be prepared into paste, liquid, foam, gel and solid shapes, foam shape is preferable from convenience for use.