The increase in immigrant populations during the last two decades in Japan has prompted the development of integration policies and practices. Numerous studies have focused on language support for migrant children; however, language support for adult migrants has received less attention. This research aims to reveal how the integration policy and language education for adult immigrants have evolved in japan and how these have contributed their socioeconomic integration. Policy analysis shows that integration policies have been underdeveloped, especially at the national level. It has been led through the inconsistency between immigration control policy, which does not overtly accept low-skilled immigrants and encourages only the entrance of highly skilled foreign workers, and the reality that there are already foreign populations with variety of backgrounds in Japan. Migrants' equal and sufficient access to language education has been hindered, while local governments and civil society has contributed to immigrants' integration through providing direct assistance and advocating the needs for such support. Differentiated inclusion of immigrants in labor market by nationalities underlines the necessity for building coherent integration policies.