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)-1H-1,2,4-triazole to optical resolution: