On March 11, the big earthquake and tsunami hit Japan creating massive destruction. Besides it, the explosion of nuclear plants forced many local residents to evacuate and escape from the effects of radiation. For those who decided to stay in the affected areas, this epic disaster brought them serious difficulties. For instance, most people were without water and electricity for more than two weeks; and almost all the gas tanks were destroyed by fire, meaning that people could not drive their cars for more than two weeks. In addition, people were forced to queue in long lines to buy daily necessities such as food, water, and clothing. People who remained in the disaster areas had no choice but to accept such difficulties.On the other hand, however, there is a possibility that facing such trauma can alter one fs behavior toward the environment: living under such severe conditions, people are forced, out of sheer necessity, to behave more pro-environmentally. To survive, they must adopt a more pro-environmental behavior. That is, people can not help experiencing saving life regardless of their intension for pro-environmental behavior. Once they accept new behavior for a saving life for a while, they can realize that current situation is not so inconvenient. Consequently, people could realize that their consumption levels before the disaster were conspicuous due to the big disaster. Considering that such experience could lead to a change of perceived behavioral control and activate subjective norms, there is the possibility that people will continue to live more simply for years after the disaster.Hence, analyzing the attitude and behavior changes after the big disaster can give us important insights into the following questions: Can a disaster lead our attitude and behavior to a more pro-environmental outlook? What kind of experience will lead to pro-environmental attitude and behavior? Analysis of the responses and suggestions to these questions would be critical to making informed public policy for sustainable development. Hence this research aims to clarify the impact of the recent natural disaster on one fs environmental attitude and behavior. In that analysis, I also analyze the psychological process in changing attitude and behavior. Finally, public policy to enhance pro-environmental behavior is discussed.To collect the data, I first conducted an interview with people who lived in evacuation centers in twenty disaster areas. A questionnaire was designed and conducted, targeting people who live in temporary houses provided by the Japanese government or a local government. Finally, statistical analyses were conducted.Results of the analyses suggest that activating subjective norm and change of perceived behavioral control contributed to attitude and behavior change as expected. Furthermore, it is suggested that seriously traumatic situations would be needed to facilitate change in environmental attitude and behavior.