This facility conveys the significance of the Besshi Copper Mine, which is the foundation of the city of Niihama. The building has a semi-underground structure that resembles a mining tunnel, and displays valuable materials related to the history, geology, mining technology, and way of life since the mine's opening. The Besshi Copper Mine Museum was established by the Sumitomo Group in 1975 to convey the significance of the Besshi Copper Mine (which was in operation from 1691 to 1973 and became the origin of the Sumitomo Group) to future generations. The Besshi Copper Mine was managed by Sumitomo for 283 years since its opening, and particularly after the Meiji Restoration, it modernized and mechanized through the introduction of Western technology, and contributed greatly to the development of related businesses based on its profits, becoming the foundation of the Sumitomo Group's various businesses seen today, as well as greatly contributing to the creation and development of Niihama City, the foremost industrial city in Shikoku. The museum displays numerous valuable historical materials related to Sumitomo and the Besshi Copper Mine since its opening, as well as materials related to ore, way of life, technology, and the overcoming of smoke pollution on Shikoku's Four-Sakishima Islands. The roof is covered with azaleas planted in commemoration of May 9, the day the mining permit was obtained, and is a famous spot for azaleas in the city, dyeing the roof bright red in May.