A composition for external application to skin, containing a compound represented by formula (I) or a salt thereof, and/or a quaternary ammonium salt represented by formula (II):wherein R1 is a substituted or unsubstituted, linear or branched chain alkyl group having 2 to 25 carbon atoms； X is —CO—NH—, —O—CO—O—, —NH—CO—, —CO—O—, —O—CO— or —O—； Y is a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms； R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms； R3 is an alkyl group having 1 to 4 carbon atoms； R2 and R3 are the same as or different from each other； R4, R5 and R6, which may the same as or different from each other, each are an alkyl group having 1 to 4 carbon atoms； and A− is a counter ion.
