The purpose of this study is to investigate the individual variables of stress, depression, psychological well-being, and perceived restorative environment among tourists who experienced nature tourism, and further to clarify relationships between the variables. A survey of tourists who visited both Suncheon Bay Wetland Reserve, one of the world's five major coastal wetlands, and Suncheonman National Garden was conducted to achieve the purpose of this study. The results of testing the research question are as follows: First, nature tourists' stress was found to show positively (+) significant predictive power for depression. Second, nature tourists' stress was found to show negatively (-) significant predictive power for psychological well-being. Third, nature tourists' perceived restorative environment was found to have a positive buffering effect on the relationship between stress and depression. Lastly, nature tourists' perceived restorative environment was found to have a moderating effect on the relationship between stress and psychological well-being. The findings of this study might have theoretical value in that it is the first attempt to clarify the positive buffering effect of perceived restorative environment on the relationship between nature tourists' stress and depression. In addition, the findings might have theoretical value in that this study is the first attempt to clarify the moderating effect of perceived restorative environment on the relationship between nature tourists' stress and psychological well-being. Further, at the practical level, the findings of this study will be applicable to travel therapy or the therapeutic area of environmental psychology as useful theoretical data and policy data.