PROBLEM TO BE SOLVED: To obtain an antimicrobial agent slight in skin irritancy and good in biodegradability.SOLUTION: This antimicrobial agent is represented by formula 1 (R1 is a 1-4C alkyl, benzyl or cyclohexyl R2 is a 1-4C alkyl or (R5-O)a-Y R3 is methyl, benzyl, cyclohexyl or (R5-O)a-Y R4 is (R5-O)a-COR6 Y is H or COR6 R5 is a 2-4C alkylene (a) is 1-5 R6 is an alkyl or alkenyl and X is an anionic atom or an anionic group).COPYRIGHT: (C)2002,JPO(修正有)【課題】 皮膚刺激性が少なく、生分解性が良好な抗菌剤を提供する。【解決手段】 一般式1(R1はC1~4のアルキル基、ベンジル基又はシクロヘキシル基を、R2はC1~4のアルキル基又は-(R5-O)a-Yを、R3はメチル基、ベンジル基、シクロヘキシル基又は-(R5-O)a-Y、R4は-(R5-O)a-COR6を、Yは水素又は-COR6を、R5はC2~4のアルキレン基を、aは1~5の数を、R6はアルキル基又はアルケニル基を、Xはアニオン性原子又はアニオン性基を表わす。)の抗菌剤。