Excelling in architectural design where Japanese and Western elements are fused, and from the fact that the preservation condition of the furniture placed inside the building is also good, in 1974 (Shōwa 49) the wooden two-story main building, and in 1980 (Shōwa 55) the annex building corresponding to the caretaker's room were designated as National Important Cultural Properties, it is a historical building representing Hakodate. It reopened on April 26, 2021.

Not to mention the impact of the entire exterior, when focusing eyes on the details, whether it is roof windows or ridge ornament fences, gables (pediments), columns, or capital decorations, whichever one you take, it is a stylish make. Among them, the VIP room on the second floor, which the imperial family has also actually used, is where foreign-made wallpaper and chandeliers, fireplaces, etc. are used, and one's eyes are captivated by the noble atmosphere of the interior.

In addition to the substantial in-building exhibition that explained the history of the public hall and features of the building, the "Costume Hall" where one can experience an exotic mood by wearing glamorous long dresses or Haikara-san style costumes is also popular. How about trying to immerse yourself in an elegant mood while changing into your favorite costume and overlooking the port from the second floor balcony? Inside the building, there is also a shop stocked with Hakodate-like products, and looking for souvenirs is also recommended.