PROBLEM TO BE SOLVED: To provide a composition containing a predetermined melanin precursor and capable of obtaining a sufficient hair dyeing property even by a single hair dyeing treatment. A composition containing the following component (A) and component (B). (A) A compound represented by the following general formula (1) or a salt thereof [wherein the broken line indicates the presence or absence of a π bond. Two R1 respectively independently shows a hydroxyl group or an acetoxy group, R2 shows a hydrogen atom or -COOR (R is a hydrogen atom, a methyl group or an ethyl group), R3 is a hydrogen atom, an acetyl group, a methyl or an ethyl group. Indicates. ] (B) A thiol compound having at least one thiol group and having a structure adjacent to the thiol group and stabilizing a thiyl radical generated due to a sulfur atom in the thiol group, or a precursor thereof. Selection diagram] None【課題】所定のメラニン前駆体を含有し、１回の染毛処理でも充分な染毛性が得られる組成物を提供する。【解決手段】次の成分（Ａ）及び成分（Ｂ）を含有する組成物。 （Ａ）下記一般式（１）で表される化合物又はその塩［式中、破線はπ結合の存在または不存在を示す。２つのＲ１は、それぞれ独立に水酸基又はアセトキシ基を示し、Ｒ２は水素原子、又は－ＣＯＯＲ（Ｒは水素原子、メチル基又はエチル基）を示し、Ｒ３は水素原子、アセチル基、メチル又はエチル基を示す。］ （Ｂ）チオール基を少なくとも１つ有し、該チオール基に隣接して、該チオール基中の硫黄原子に由来して生成するチイルラジカルを安定化させる構造を有するチオール化合物、又はその前駆体【選択図】なし
