In January 2018, Nichibunken Library registered the some 300,000 titles of the Japanese and non-Japanese works in its collection with the OCLC WorldCat, through a tie-up with Kinokuniya Shoten. Of that data about 170,000 entries have been newly added to the WorldCat. From April 2018, moreover, Nichibunken also started to provide interlibrary loan and document delivery services through the OCLC WorldShare ILL. Participation by libraries in Japan has been limited to only a few institutions including the National Diet Library and Waseda University, and Nichibunken is the first one among national universities and research institutions in Japan. Through this service, we succeeded to improve operations of international ILL/DDS, and researchers around the world can find and gain use of the materials in the Nichibunken more smoothly.