In this paper, we describe how synthesized populations are essential in real-scale social simulations (RSSS), and the current situation of the population synthesis for whole populations in Japan. RSSS is simulations using the real number of populations or households in social simulations. This paper describes how we have completed to synthesize multiple sets of populations based on the statistics of each local government in Japanese national census in 2000,2005,2010 and 2015. We have started to distribute those multiple sets of the synthesized populations for researchers of RSSSs in Japan. In distributing the synthesized populations, we should set some regulations in order to protect personal or private information in the synthesized populations.