The role of the City of Hiroshima in Gorbachev's diplomacy has changed in proportion as the so-called policy of 'Perestroika' has developed, with the following peculiarities. (1) March 1985 - April 1986 At this time the Soviet government intended to draw the American government in the unilateral cease of nuclear tests. The City of Hiroshima as the symbol of the world peace was the instrument for the Soviet government to make the world public opinion for peace and to strengthen the peace offensive. (2) April 1986 - May 1986 At this time the accident of the Chernobyl atomic power-station happened. The City of Hiroshima was assigned the task of holding the summit meeting between the Soviet Union and the United States for the ban of nuclear tests. (3) April 1986 - July 1986 At this time Soviet foreign policy toward Asia-Pacific region changed into attaching greater importance to economic cooperation. The City of Hiroshima as so-called 'Helsinki of Asia-Pacific region' was assigned the task of holding the 'Pacific Conferrence'. (4) February 1987 - today At this time the doctorin of nuclear deterrance was denied in the Soviet Union. It was emphasized in particular that the tragedy of Hiroshima is an alarm bell for the mankind. The City of Hiroshima was assigned the task of continuing to be the symbol of disarmament and human welfare. The mayer of the City of Hiroshima delivered 'Peace Declaration' August 6, 1989. He first requested the Japanese government to curb its military spending and take the initiative in diplomatic efforts for peace. He also first requested the government to work for the non-nuclearization of Asia-Pacific region and establish policies to keep the three non-nuclear principles. At the same time it seems that he requested the US government to reconsider the strategy of nuclear deterence. A city has many limitations in the field of diplomacy. But a city can take advantage of the opportunity of today's Soviet-US cooperation. The City of Hiroshima, with the City of Nagasaki, as a central member of Wo