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:
