A hair treatment method comprising steps (i) to (iii):step (i): a step of applying a hair treatment agent containing components (A) and (B) to hair;step (ii): a step of leaving the hair to stand, after step (i); andstep (iii): a step of applying a hair treatment agent containing component (C) to the hair, after step (ii),(A) a compound selected from the group consisting of a glycylglycine derivative, a polyglycerin, and an alkyl glyceryl ether;(B) a 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;(C) an aromatic sulfonic acid having a molecular weight of 300 or less, or a salt thereof.