is a subway station in Chiyoda, Tokyo, Japan, operated by the Tokyo subway operator Tokyo Metro. It is located adjacent to the National Diet Building. The station name literally means "in front of the National Diet Building". Lines Kokkai-gijidomae Station is served by the following lines. Tokyo Metro Marunouchi Line (M-14) Tokyo Metro Chiyoda Line (C-07) The station is also connected by underground passageways to Tameike-sannō Station, which is served by the Ginza and s, and it is possible to transfer between the two stations without passing through the ticket gates. Station layout The Chiyoda Line platforms are 37.9 m underground, making this station the deepest in the Tokyo Metro network (although a number of stations on the are farther underground). History The station first opened on March 15, 1959, as a station on the Marunouchi Line. The Chiyoda Line platforms opened on October 20, 1972. It also became possible to transfer to the Ginza and Namboku lines via a passageway to the newly opened Tameike-Sannō Station which opened on September 30, 1997. The station facilities were inherited by Tokyo Metro after the privatization of the Teito Rapid Transit Authority (TRTA) in 2004. Surrounding area National Diet Building Prime Minister's Official Residence (Japan) Cabinet Office Hibiya High School Hie Shrine The Capitol Hotel Tokyu References External links Kokkai-gijidomae Station information (Tokyo Metro) Railway stations in Tokyo Stations of Tokyo Metro Tokyo Metro Marunouchi Line Tokyo Metro Chiyoda Line Railway stations in Japan opened in 1959