As the extension work progressed, the Diet Service Section--which was located in the Miyakezaka temporary building on the site of the former General Staff Office Building (now known as the Kensei-Kinenkan (Constitution Memorial Center) located in the north area of the front garden of the Diet Building)--merged into the NDL Main Library, completing the consolidation of the NDL's functions previously spread among three areas: Akasaka, Ueno and Miyakezaka.
増築の進捗にともなって旧参謀本部庁舎跡地（現国会前庭北地区・憲政記念館）の三宅坂仮庁舎に置かれていた国会サービス部門も本館内に移転し、赤坂・上野・三宅坂の3地区に分かれていた国会図書館の機能は最終的な統合をみる。