Provided is a powdery composition that contains components (A), (B) and (C). Also provided is a kit for hair dyeing or hair bleaching, which is constituted from a first composition comprising the powdery composition and a second composition containing hydrogen peroxide. Component (A): an alkanolamine having a SP value, as measured using the Fedors method, of 10-16 (cal/cm3)1/2, or a salt of the alkanolamine. Component (B): a compound (excluding compounds that correspond to component (A)) the SP value of which, as measured using the Fedors method, is within ±6 (cal/cm3)1/2 of the SP value of the alkanolamine of component (A). Component (C): a powdery carrier.本發明係一種含有下述成分(A)、(B)及(C)之粉末狀組合物。本發明係一種染毛用或毛髮脫色用套組，其包括包含該粉末狀組合物之第1組合物與含有過氧化氫之第2組合物。 成分(A)：藉由Fedors法所獲得之SP值為10(cal/cm3)1/2以上且16(cal/cm3)1/2以下之烷醇胺、或該烷醇胺之鹽 成分(B)：藉由Fedors法所獲得之SP值為成分(A)之烷醇胺的SP值±6(cal/cm3)1/2以內之化合物(但，屬於成分(A)之化合物除外) 成分(C)：粉末狀載體
