To provide a triazole compound which has remarkably excellent pesticidal activities. Optically active (+)-1-[2-fluoro-4-methyl-5-(2,2,2-trifluoroethylsulfinyl)phenyl]-5-amino-3-(trifluoromethyl)-1H-1,2,4-triazole represented by the following formula (I), which is obtainable by subjecting a racemic modification of 1-[2-fluoro-4-methyl-5-(2,2,2-trifluoroethylsulfinyl)phenyl]-5-amino-3-(trifluoromethyl)-1 H-1,2,4-triazole to optical resolution:현저하게 우수한 유해생물 방제 활성을 가지는 트리아졸 화합물을 제공한다.하기 식(I)으로 표시되는 광학 활성 (+)-1-[2-플루오로-4-메틸-5-(2,2,2-트리플루오로에틸술피닐)페닐]-5-아미노-3-(트리플루오로메틸)-1H-1,2,4-트리아졸. 1-[2-플루오로-4-메틸-5-(2,2,2-트리플루오로에틸술피닐)페닐]-5-아미노-3-(트리플루오로메틸)-1H-1,2,4-트리아졸의 라세미체를 광학 분할하여 얻어진다.
