KSP2016-1577) A method for treating hair, comprising the following steps: step (i): a step of applying a first composition comprising carboxylic acid having an inorganic value of 250 to 450 and an organic value of 50 to 250, or a salt of the carboxylic acid, as a component (A), to hair, step (ii): a step of leaving the hair, to which the first composition has been applied, at a temperature of 15°C to 10 0°C for 15 seconds to 60 minutes, and step (iii): a step of applying a second composition comprising aromatic sulfonic acid or a salt thereof having a molecular weight of 3 00 or less, as a component (B), to the hair after completion of the step (ii). 62
