The below-mentioned general formula (1)The sugar residue, or the below-mentioned constitutional formula where [in formula, R1 the hydrogen atom, the alkaline metal, the alkaline earths metal and the succession metal, the ammonium, or carbon count shows alkyl group or the arukeniru basis 1, of displacement or the unsubstituted - 22 R2, as for R3 and R4 in the respective independence, possesses the hydrogen atom, the amino group or the amide basis (2)(In formula, as for n integer 1 - 10)So it is the univalent basis which is displayed, R2, R inside3 and R4, at least one the sugar residue, or the above-mentioned constitutional formula which possesses the amino group or the amide basis is the univalent basis which is displayed with (2). ]So feel of the fiber hair and the like it improves the gallic Acid derivative which is displayed, it possesses high adsorbability vis-a-vis the keratin protein, the external use agent composition which contains this gallic Acid derivative raises the hair adsorbability of useful component gallic Acid derivative, itself and such as medicine and the conditioning medicine which are jointly used long term can maintain these effects.下記一般式(1)[式中、R1は水素原子、アルカリ金属、アルカリ土類金属、遷移金属、置換もしくは非置換のアンモニウム、又は炭素数1~22のアルキル基もしくはアルケニル基を示し、R2、R3及びR4はそれぞれ独立に、水素原子、アミノ基もしくはアミド基を有する糖残基、又は下記構造式(2)(式中、nは1~10の整数)で表される一価の基であり、R2、R3及びR4のうち、少なくとも一つはアミノ基もしくはアミド基を有する糖残基、又は上記構造式(2)で表される一価の基である。]で表される没食子酸誘導体は、繊維・毛髪等の感触を良くし、ケラチンタンパク質に対して高い吸着性を有し、この没食子酸誘導体を含有する外用剤組成物は、没食子酸誘導体そのものや、併用する薬剤やコンディショニング剤等の有用成分の毛髪吸着性を高め、これらの効果を長期維持できる。
