Disclosed is a method that is for producing 1-bromo-1-[3,5-bis(trifluoromethyl)phenyl] ethane having high optical purity, and that is a method containing a step for brominating optically active 1-[3,5-bis(trifluoromethyl)phenyl] ethanol using, as a brominating agent, either a) the combination of a phosphorus halide and hydrogen bromide, b) the combination of 1,2-dibromo-1,1,2,2-tetrachloroethane and the organophosphorus compound represented by general formula I, which is P(R1)(R2)(R3) (in the formula: R1, R2 and R3 each independently indicate a C6-10 aryl group, a C6-10 aryloxy group, a C1-10 alkyl group, a C1-10 alkoxyl group, a C3-6 cycloalkyl group, or a C3-6 cycloalkoxyl group), or c) the combination of N-bromosuccinimide and a dialkyl sulphide.