Mizuho Bank, Ltd. is the integrated retail and corporate banking unit of Mizuho Financial Group (TYO:8411; NYSE:MFG), one of the largest financial services companies in Japan, with total assets of approximately $1.64 trillion in 2014. Mizuho is one of the three so-called Japanese "megabanks" (along with Mitsubishi UFJ Financial Group and Sumitomo Mitsui Financial Group). Mizuho Bank provides financial products and services to a wide range of clients, including individuals, small and medium-sized enterprises, large corporations, financial institutions and public sector entities. Its headquarters office building is located in the Otemachi district of Chiyoda, Tokyo.

Mizuho Bank has over 505 branches and offices in Japan and in thirty-six other countries and regions, and is the only bank to have branches in every prefecture in Japan.