Its facilities consist of the "main libraries," which include the Tokyo Main Library (Nagata-cho, Chiyoda Ward, Tokyo Prefecture) and the Kansai-kan of the National Diet Library (Seikadai, Seika-cho, Soraku-gun, Kyoto Prefecture), as well as the "branch libraries," including the International Library of Children's Literature (Ueno-koen, Taito Ward, Tokyo Prefecture), the Toyo Bunko (Oriental Library) (Honkomagome, Bunkyo Ward, Tokyo Prefecture) and 26 libraries in the executive and judicial agencies of the government, etc.
施設は、「中央の図書館」として東京本館（東京都千代田区永田町）および国立国会図書館関西館（京都府相楽郡精華町精華台）が置かれ、「支部図書館」として国際子ども図書館（東京都台東区上野公園）、東洋文庫（東京都文京区本駒込）のほか、行政機関・司法機関などに26館が置かれる。