To provide a multiagent-type hair treatment agent and hair-treating method in which not only taking shape when drying wet hair but also styling/arranging of hair after drying are also enhanced, and furthermore smoothness can be imparted to hair.SOLUTION: A multiagent-type hair treatment agent comprises a first composition containing a component (A) and a component (B), and a second composition containing a component (C), and a mass ratio (H)/(C) of a component (H) with respect to the component (C) is less than 1 in the second composition. A hair-treating method includes: a process (i) of applying hair with the first composition and rinsing the composition； and (ii) a process of then applying the hair with the second composition. The component (A): carboxylic acid in which an inorganic value is 230 or more and 450 or less and an organic value is 50 or more and 250 or less, or salt of the carboxylic acid, the component (B): anionic surfactant, the component (C): aromatic sulfonic acid whose molecular weight is 300 or less, or salt thereof, and the component (H): cationic surfactant.SELECTED DRAWING: None【課題】濡れ髪を乾燥させたときのまとまり性だけでなく、乾燥後の毛髪に対する形付け性をも高め、更に毛髪に滑らかさを付与することができる多剤式毛髪処理剤及び毛髪処理方法の提供。【解決手段】成分(A)及び成分(B)を含有する第一の組成物、並びに成分(C)を含有する第二の組成物を備え、第二の組成物において成分(C)に対する成分(H)の質量比(H)／(C)が１未満である、多剤式毛髪処理剤。毛髪に前記第一の組成物を適用してすすぎ流す工程（ｉ）、及びその後毛髪に前記第二の組成物を適用する工程（ii）を含む毛髪処理方法。 成分(A)：無機性値が230以上450以下でかつ有機性値が50以上250以下であるカルボン酸、又は当該カルボン酸の塩 成分(B)：アニオン性界面活性剤 成分(C)：分子量が300以下の芳香族スルホン酸又はその塩 成分(H)：カチオン性界面活性剤【選択図】なし
