Disposers are the kind of instruments for the improvement of our living conditions, but a serious problem seems to be caused in the sewage disposal. Then various effects of them on environmental, economical and social factors were derived from the application of the impact matrix method. The awareness of these effects were found out by means of a questionary surveyfor about 500 persons who are engineers working in sewage and refuse fields, disposers-users and so on. Persons of 18.3% want to use disposers, but persons of 51.7% are opposed to them becauseof bad influences of sewage treatment processes. Disposers wewe evaluated by the impact matrix method (without weight and weighted) maily based on the survey. They were almost preferable inrefuse processes, and on the contrary, were not in sewage processes. Consequently, disposers arenot available for the ordinary sewage treatment processes. If you want to use them, you should bear the greater part of expenses of additional measures against water pollution.