PROBLEM TO BE SOLVED: To provide a composition by which at least some of the problems associated with the composition of a prior art is wrestled or overcome, and specifically to provide a composition with a less unpleasant odor of ammonia having a sufficient viscosity to remain on the desired region of keratin fibers for a sufficient time to change the color of the keratin fibers.SOLUTION: The invention provides a cosmetic composition for keratin fibers containing (i) an alkali-containing composition containing at least one kind of alkali agent, at least one kind of fat substance, and at least one kind of surfactant, and (ii) a developer composition containing at least one kind of oxidant, at least one kind of fat substance, and optionally at least one kind of surfactant. The amount in the mass% of at least one kind of surfactant in the alkali-containing composition exceeds the amount in the mass% of at least one kind of fat substance in the alkali-containing composition. The total amount of the fat substance in the cosmetic composition is at least 10 mass% to the mass of the cosmetic composition, and the mass ratio of (the total amount of the surfactant in the cosmetic composition) to (the total amount of the fat substance in the cosmetic composition) is 0.7 or more.SELECTED DRAWING: None【課題】先行技術の組成物に伴う問題のうちの少なくとも幾つかに取り組む又は克服する組成物を提供すること、詳細にはアンモニアの不快な臭いが少なくてケラチン繊維の色を変えるのに十分な時間ケラチン繊維の所望の領域上に留まるのに十分な粘度を有する組成物を提供すること。【解決手段】(i)少なくとも1種のアルカリ剤、少なくとも1種の脂肪物質、及び少なくとも1種の界面活性剤を含むアルカリ含有組成物と、(ii)少なくとも1種の酸化剤、少なくとも1種の脂肪物質、及び任意選択で少なくとも1種の界面活性剤を含む顕色剤組成物とを含有する、ケラチン繊維用の化粧用組成物を提供する。アルカリ含有組成物中の少なくとも1種の界面活性剤の質量%での量は、アルカリ含有組成物中の少なくとも1種の脂肪物質の質量%での量を超える。化粧用組成物中の脂肪物質の総量は、化粧用組成物の質量に対して少なくとも10質量%であり、(化粧用組成物中の界面活性剤の総量)対(化粧用組成物中の脂肪物質の総量)の質量比は、0.7以上である。【選択図】なし
