This paper reviews the role of Consistency Index of Analytic Hierarchy Process (AHP). On the hypothesis that the index is able to discriminate the consistency of judgments, discriminating power of the index is verified. The verification is carried out through survey questionnaire consisting of questions asking the same issue in different ways; one using so called ranking method, the other requires respondents to conduct pairwise comparisons. The result implies that the Consistency Index may not be able to distinguish the consistency of judgment.