PROBLEM TO BE SOLVED: To provide an intermediate treatment agent for hair dyeing with improved hair dyeing strength, a hair treatment setting agent, and a method of applying the hair treatment setting agent.SOLUTION: The method of applying a hair treatment setting agent comprises: a step of applying an oxidizing hair dye in which an alkali agent and an oxidizing agent are blended to hair； a step of applying thereon an intermediate treatment agent for hair dyeing comprising at least one reducing sugar selected from the group consisting of (A) pentose, hexose, heptose, reducing disaccharides, and reducing oligosaccharides； and a step of washing off the oxidizing hair dye and the intermediate treatment agent for hair dyeing which were applied to the hair.SELECTED DRAWING: None【課題】染毛力を向上させた染毛用中間処理剤、毛髪処理セット剤、及び毛髪処理セット剤の使用方法を提供する。【解決手段】本発明は、アルカリ剤及び酸化剤を混合した酸化染毛剤を毛髪に塗布する工程、（Ａ）五炭糖、六炭糖、七炭糖、還元性二糖類、及び還元性オリゴ糖から選ばれる少なくとも一種の還元糖を含有する染毛用中間処理剤をその上に塗布する工程、毛髪に塗布した酸化染毛剤及び染毛用中間処理剤を洗い流す工程を含む毛髪処理セット剤の使用方法である。【選択図】なし
