As a part of the study group's work on Optimization of Nuclear Safety Regulation of JSME, we studied the current experience and information about Containment Leakage Rate Testing (CVLRT) in the U.S. and European countries. After that, we compared their methods with the methods of CVLRT used in Japan. The results of our studies were summarized as follows: 1) In the U.S., NRC de-regulated the CVLRT methods so that the utilities could select the most efficient and the safest method. 2) In France and Belgium, the OLM (Online Leakage Monitoring) is used.