The affiliated libraries of the Executive and Judicial agencies of the government (Cabinet Office Library, branch of the NDL; Supreme Court Library, branch of the NDL, etc.) deposit materials published by the agencies to which they belong, and collect and store the materials necessary for their duties; although these libraries are operated under the budget of each agency, they are included in the NDL organization as branch libraries of the NDL.
行政・司法各部門の附属図書館（支部内閣府図書館、支部最高裁判所図書館など）は、設置母体の省庁の刊行物を収めたり業務上必要な資料を収集し所蔵しており、それぞれの省庁の予算によって運営されるが、同時に制度上で国立国会図書館の支部図書館として国立国会図書館の組織に包括されている。