The Eisei Bunko Museum (永青文庫, Eisei Bunko) is a museum in Bunkyo-ku district in Tokyo, Japan. Its collection includes historical documents and artifacts, and works of fine art. The museum is located what was formerly the grounds of the Hosokawa clan, near the Shin-Edogawa Garden.
The Eisei-Bunko (Eisei Archive) is a collection of important art objects acquired and passed down in the Hosokawa family, a daimyo of 540 thousand-goku (one of the five top daimyos) in Higo, the present day Kumamoto in Kyushu. The collection has been in existence since the Nanboku-chō Era or the 14th century and is noted for possessing close to 112 thousands objects. In 1950, the archive was turned into a foundation and a public museum was opened in 1973. Currently the display at the museum is rearranged three times a year at which occasion special events are organized for its members.
The collection consists of over 100 thousands rare and old documents, scrolls, paintings, etc. and approximately 6000 objects of art, including crafts, modern paintings and sculptures acquired here and abroad. These are only estimated figures of the "legendary archive" whose content and exact size still remain unknown. The archive materials have been placed in the care of Kumamoto University for analysis while art objects are being exhibited at the museum in parts as they are catalogued.