The Signature Campaign against Atomic and Hydrogen bombs in 1954 caused the nationwide movement against A- and H-bombs in Japan. The purpose of this paper is to explicate characteristics of the Japanese movement against A- and H-bombs through the examination of the Signature Campaign. Especially, this paper tries to show the following four points. 1. When the crew of the Daigo-Fukuryumaru received heavy doses of radiation in the hydrogen bomb test conducted by the United states on Bikini Atoll in the Marshall Islands on March 1954, Japanese called for not only a ban on the hydrogen bomb test, but also a ban on all military uses of nuclear energy. The origin of this was the experiences of Hiroshima and Nagasaki. 2. The Campaign was carried on not only by groups of ordinary citizens or grass-roots people, but supported also by the National Diet, local assemblies and national peace groups. 3. The Campaign was led mainly by groups independent of international peace movement groups such as World Peace Bureau. 4. The effects and achievements of the Campaign varied in different localities.