In the U.S., Cognitive Behavioral Therapy such as ERP has become a standard treatment for the patients with Obsessive-Compulsive Disorder. In some cases, however, trying to correct cognitive contents exacerbates obsessions. 2 OCD cases are illustrated to which Inpatient Morita Therapy was applied after the trial of Cognitive Behavioral Therapy and showed a favorable progress. Morita Therapy is founded by Shoma Morita in1919 in Japan, and based on Eastern psychology. Inpatient Morita Therapy and Outpatient Morita Therapy are introduced in this book. Since the beginning of the 1990s, a new trend of cognitive-behavioral therapy, called "The Third Wave, " has begun to appear in the U.S. Acceptance and Commitment Therapy (ACT) developed in 1999 is representative of such trend. Hofman, S.G. published an article, "Acceptance and Commitment Therapy: New Wave or Morita Therapy?" in 2008, and argued that ACT is not a new wave but is conceptually very similar to Morita Therapy. Because this study focuses on cases to compare ACT and Outpatient Morita Therapy.