Nihonbashi Icchōme Mitsui building, Corporate skyscraper in Nihonbashi, Tokyo, Japan.

The Nihonbashi Icchōme Mitsui Building is a 20-storey tower (four basement levels) at the Nihonbashi intersection, completed in 2004. Its lower floors hold the COREDO Nihonbashi retail complex, while floors 6 to 19 are offices reached by eight shuttle elevators from the first floor. The fifth floor houses Waseda University's Nihonbashi campus.

Completed in January 2004 on the site of the Tokyu Department Store Nihonbashi branch, which closed in 1999, the tower opened as the Nihonbashi Icchome Building on 30 March 2004. It was renamed Nihonbashi Icchome Mitsui Building in 2014. The project was led by Mitsui Fudosan and Tokyu Fudosan, with Tokyu selling its 30% stake to Mitsui in 2004.

The retail zone is named COREDO Nihonbashi, a coined word combining CORE (centre) and EDO, meaning "the centre of Edo". It opened on 30 March 2004 with 33 shops; the Takara concept store Garage closed on 10 July 2005 and the Serendipity store on 22 February 2009. The fifth floor, formally retail space, houses Waseda University's Nihonbashi campus, opened as WASEDA NEO in July 2017.

The building connects directly to Nihonbashi Station, which serves three metro lines and provides easy access for visitors. This central location makes it simple to reach by public transportation and explore the surrounding neighborhood.

The 12th floor holds OASIS, a shared welfare space for office tenants with bento sales, health checks, exercise programmes, body care, massage chairs and nap booths. The 5th floor, planned as retail, instead houses Waseda University's Nihonbashi campus, opened as WASEDA NEO in July 2017.