Evaluation is necessary in implementation of any project or policy, including those related to environmental problems. In our complex society, how to evaluate, how to fulfill accountability, and how to achieve agreement are problematic. In the environmental sciences, some methods have already been developed as decision aids. However, these methods cannot yet be used to adequately handle diversity, complexity, and uncertainty. Therefore, we investigated the possibility of using multi-criteria analysis for environmental evaluation and development of decision aids. In this study, we conducted a trial experiment of a garbage treatment system, and focused on differences in the judgments made by plural evaluators. This was an attempt to use a multi-criteria analysis as a decision aid when more than one person is involved. In recent years, some applications of multi-criteria analysis to environmental fields have been reported. Thus, it has become necessary to restructure the framework of research within the current state of the field. In this paper, first we outline the past research on the application of multi-criteria analysis to environmental problems in recent years, focusing on Europe. Next, we examined the results and the problems of past studies in order to discuss future studies. JEL Classification: D70, D81, D82, Q51, D53