"Marunouchi gate" of Tokyo Station

Marunouchi (丸の内) is a commercial district of Tokyo located in Chiyoda Ward, between Tokyo Station and the Imperial Palace. The name, meaning "inside the circle", derives from its location within the palace's outer moat.

It is known as the center of Japan's financial industry. Companies based in the area include Mizuho Bank, Bank of Tokyo-Mitsubishi, and Sumitomo Bank, Japan's three largest banks. Tokio Marine and Fire Insurance, one of Japan's largest casualty insurance providers, is based in Marunouchi.

Marunouchi also houses the Japan offices of Banca Commerciale Italiana , Bankers Trust, Bank Negara Indonesia , Bank of India, Bayerische Landes Bank , Bloomberg, BT Asia Securities , First National Bank of Boston , Mellon Bank , Overseas Union Bank , Philadelphia National Bank , Royal Insurance , Standard Chartered Bank.

The 37-story Marunouchi Building is said to sit atop the most expensive real estate in Japan, with a land value of ¥21 million/m².

Tokyo's central post office is located in Marunouchi, adjacent to Tokyo Station.