This is a historic building representative of Hakodate, designated as a National Important Cultural Property—the main two-story wooden building in 1974 (Showa 49) and the attached building, which served as the caretaker's room, in 1980 (Showa 55)—for its excellent architectural design that fuses Japanese and Western elements and the good condition of the furniture inside. It reopened after renovations on April 26, 2021.

While the overall impact of the exterior is impressive, a closer look at the details reveals that everything from the dormer windows, roof cresting, pediments, columns, and capitals is of a stylish, modern design. Among these, the VIP room on the second floor, which was once used by the Imperial family, is particularly captivating with its noble interior atmosphere, featuring foreign-made wallpaper, chandeliers, and a fireplace.

In addition to the extensive exhibits inside the hall that explain its history and architectural features, the 'Costume Hall' is also popular, where visitors can experience a foreign atmosphere by wearing glamorous long dresses or 'haikara-san' (modern girl) style outfits. Why not change into your favorite costume and immerse yourself in an elegant mood while enjoying a panoramic view of the port from the second-floor balcony? There is also a shop inside the hall with a selection of products characteristic of Hakodate, which is recommended for finding souvenirs.