Health inequality has long attracted keen attention in the research and policy arena. While there may be various motivations to study health inequality, what distinguishes it as a distinct topic is moral concern. Despite the importance of this moral interest, a theoretical and analytical framework for measuring health inequality acknowledging moral concerns remains to be established. The development of a sound theoretical and analytical framework for measuring health inequality sensitive to relevant moral concerns is crucial for understanding what the problem is in ubiquitously observed health inequalities and moving onto effective policy-making. This study aims to contribute to meeting such a need. This study will first propose a framework for measuring health inequality through classification of confusing terminologies used in the field, examination on ways to conceptualize and measure health as the focus of equalization, and investigation on distributional concerns by which a health distribution is judged to be more (or less) equal. Second, this study will show how the ideas discussed can be used in quantitative studies. Two empirical examples will be presented based on two different conceptions of health equality derived from the conceptual analyses in the first part of this research. The first example, using the Japanese Comprehensive Survey of Living Conditions of the People on Health and Welfare in 1986 and 1998, will examine a trend in health inequality in Japan based on the conception of equality in the minimally adequate level of health. The second example, using the U.S. National Health Interview Survey in 1990 and 1995, will take the view that health inequality becomes our moral concern when it is pervasive. This second example will show how health inequality measures, which reflect different distributional concerns, might describe a health distribution differently. The uniqueness of this study lies in the marriage between philosophy and qualitative methodologies. This research will be valuable as a guide book for anyone, from the academic to a policy-maker, who is concerned about moral implications of health inequality in populations of various types and sizes.