It is not known exactly when Shosoin was built, but it is generally accepted as around 756, when Empress Komyo dedicated the late Emperor Shomu's favorite articles to the Daibutsu.
建立時期は不明だが、光明皇后が夫聖武天皇の遺愛の品を大仏に奉献した756年（天平勝宝8）前後とみるのが通説である。