The unfairness of the tax structure has been identified as one of the important causes of tax avoidance, yet no clear conceptual framework has been established in this regard. Since the tax structure can be understood as a dynamic behavioral system, taxpayers' perceptual criteria are critically important in judging its fairness. In this study, to grasp the concept of tax fairness from the taxpayer's perspective, a multidimensional model was constructed based on existing theories of tax justice, and an experiment was conducted. The existence of a dominant tax justice criterion—a concept necessary for the stable maintenance of social structure—was confirmed, and the need-based criterion, which emphasizes the guarantee of minimum living conditions, emerged as the most important perceptual criterion for tax fairness.