Abstract
Civil lawsuits relating air pollution health effects presented often times in Japan. As a evidence of causal relation between air pollution exposure and respiratory diseases, epidemiological studies were submitted to the courts. An interpretation of these studies by judges were markedly different and unique from ordinal epidemiological understanding; scientific understanding of the studies. Based on these unique implication of the evidence, the judgment announced forcefully recognizing a existence of causal relationship between exposure to pollution and disease outcome. The author wishes to let epidemiologists know the details of this phenomena, hoping a correct usage of epidemiology in the course of deciding judgment at civil lawsuit.