Some parts have been rebuilt in the style of the Kamakura period as changed from the Kirizuma-zukuri style (a style of building with a gable roof) to the Irimoya style (a style of building with a half-hipped roof), but the building is still precious as the only ancient structural remnants of Heijo-kyu Palace.
切妻造を入母屋にしたり、鎌倉時代の様式で改造されている箇所もあるが、平城宮唯一の建築遺構として貴重である。