In this paper, I propose to look at the separation of prescription and dispensing in Japan（Iyakubungyo）from the point of view of social science and aim to clarify factors of promotion of Iyakubungyo. Today, the separation rate reached over 60%, and it shows Iyakubungyo comes into a common system. However the system has not been judged socially, because there is no paper about the social evaluation of Iyakubungyo while there are some papers about the factors of the satisfaction of patients. There are some investigations of how to promote Iyakubungyo, but no investigations of why. I will figure out factors of promotion of the separation of prescription and dispensing in Japan by verifying two policies, “the divorce between things and technique” and “proper use of pharmaceutical products”. A change of these policies makes the change of contents and rates of Iyakubungyo. By showing the possibility that the two policies were the factors of the development of Iyakubungyo, we can get a hint for finding the pharmacists’ function in social.