This paper is described about the collaboration of two top political parties, "Minseito" and "Seiyukai", that cooperated in order to process Manchurian Incident and the Showa Depression which occurred in 1931.In September 1931, persisting with the expansion of interests in northeastern China, the Kwantung Army blew up the Manchuria Railway and, blaming it on the Chinese Army, launched military action and imposed military rule on Mukden.Wakatsuki Reijiro's Government tried to prevent the military action from spreading, but was ignored by the Kwantung Army and eventually Wakatsuki's Government ratified the military's policy. The fact that the government had no control over the military aggravated the situation. The Manchurian Incident deepened the with America and Britain.The Great Depression which happened in 1929 gave the serious damage to economy of Japan. Japan exported a gold again to recovery the Gold standard, and to reorganize finances in 1930. However, the confusion of the economy in Japan started the Showa Depression.The takeover of Manchuria proved to be turning point in both domestic and foreign policy. Prime Minister Wakatsuki who was Presidents of "Minseito" tried to defend rule by government parties. The government had no control over the military. Then, the movement which organizes the collaboration Cabinet of "Minseito" and "Seiyukai" started. Although it was for this movement maintaining the politics by a political party, the collaboration Cabinet was not formed. Therefore, party politics collapsed.