The Mizuho Bank Uchisaiwaichō Head Office Building (みずほ銀行内幸町本部ビル, Mizuho Ginkō Uchisaiwaichō Honbu Biru) is a 143 m (469 ft) tall skyscraper in Tokyo, Japan. At 38 stories the building is the 86th tallest building in Tokyo. It contains 1.4 million sq ft (134,974 m²) of office space, 100% of which is now occupied by Mizuho Bank, the consumer banking arm of the second-largest Japanese financial conglomerate Mizuho Financial Group, while still called the DKB Head Office from time to time.
The building was built in Chiyoda at 1 Uchisaiwaichō in 1981, when it was called the Dai-Ichi Kangyo Bank Head Office Building. It was designed by architects Yoshinobu Ashihara & Partners and developed by Shimizu Corporation, one of the “big five” real estate developers in Japan. Dai-Ichi Kangyo Bank (“DKB”) combined with Fuji Bank and the Industrial Bank of Japan in 2000 to form Mizuho Financial Group.