The museum houses over 20,000 natural history specimens, with its primary distinction being the extensive Yoshimura Collection of taxidermy. This collection, assembled by naturalist Yoshimura Shōzaburō, features mammals, birds, and fauna from around the world displayed in elaborate dioramas. The sheer scale and quality of preservation make it one of Japan's most comprehensive taxidermy collections, offering visitors an immersive look at global biodiversity under one roof.