In this research, the authors focus on frequently reported inappropriate behaviors conducted by the elderly with dementia in the environment of residential facilities. These inappropriate behaviors tend to be taken as problem behaviors by others and often trigger restriction of certain kinds of residents' behaviors by the caring staff. In this research, we intend to take as many of these behaviors as possible as behavioral errors brought by the residents' misunderstanding of the information embedded in surrounding environment. In a previous presentation (Yokoyama et al., 2008), the authors surveyed these behavioral errors in the 2 main types of the residential facilities in Japan, i.e. nursing homes and group homes, and suggested that the environmental differences between the 2 facility types might bring differences in numerical distribution of the categories of behavioral errors. Here, in this presentation, 167 cases of the residents' behavioral errors were collected by interviewing the trained care staff of nursing homes. The authors carefully observed the environment where each of the reported behavioral errors was found, and by showing photographs of it, they further argue in which situation and how the behavior happens. Finally, the argument suggests that some behavioral errors should be caused by misleading or absence of the information embedded in the environment. In the main part, the behaviors of spatial disorientation and wandering about, and those accompany urinary or excretory problems and/or sanitary troubles are discussed. These are included in the most problematic behaviors that burden the caring staff and the findings would support designing better residential environment, from the aspect of enabling environment and from the aspect of better environment also for the caring staff.