This article attempts to analyze the policy-making process of Japanese Constitution after the Japanese government had sent its replay of August 10,1945 to the Allies indicating its willingness to surrender. This author believes that General MacArthur, in his capacity as Supreme Commander of the Allied Powers, played as an pivotal role in his settling down to the task of disarming Japan, eradicating all the mainsprings of militarian and aggressive nationalism; and democratizing its whole structure and way of life. MacArthur was given wide exigencies that was developed. Obviously, the making of Japanese Constitution is, in many respects, that of the personal rule of General MacArthur. s