The present invention relates to an improved method for producing a diphenylmethane derivative which is effective as a sodium-dependent glucose cotransporter (SGLT) inhibitor, the method being carried out by means of a convergent synthesis method in which each major group is separately synthesized and then coupled. As such, in comparison to a linear synthesis method disclosed in existing documents, the synthesis pathway is compact and yield can be increased, and risk factors inherent in the linear synthesis pathway can be reduced. Furthermore, the crystal form of the compound produced according to the method has superb physicochemical characteristics, and thus can be effectively utilized in fields such as pharmaceutical manufacturing.