Social Science Japan Data Archive (SSJDA) has been developing DDI implementation projects. We present ongoing projects and future tasks in SSJDA. In 2018, we are authorized by Japan Society for the Promotion of Science (JSPS) as a Core Institution for Constructing Data Infrastructure for the Humanities and Social Sciences. Now, users can access more than 1,500 datasets and metadata. Our preexisting metadata is not based on the DDI format. We are making them into DDI 2.5 format. We plan to make metadata in the DDI format (DDI 2.5) and to integrate metadata in the DDI format into our existing metadata browsing and data download system and improve the process of data archiving work. But we have some problems with DDI implementation projects. For example, we can't make DDI format metadata as routine work because our systems are in the development stage. Discuss these projects and future issues.