This paper questions whether personal income comparison explains the distributive gap between income and class identification by exploring the following two issues: empirical validity of income comparison as the determinant of class identification, and theoretical validity of income comparison for the distributive gap. For the first issue, we conduct a statistical analysis using data from the Social Stratification and Social Mobility surveys , and the Stratification and Social Psychology-I survey (2010). We find that the criteria for choosing reference groups changed historically from residential proximity to occupational equality. In addition, income comparison with sensitive to lowerincome possessors and a distorted perception of income difference significantly affected class identification, except for the year of 1985. The simulation analysis employed to examine the second issue clarified that income comparison with the above-mentioned features yields a less skewed distribution compared to that of class identification. The data also indicates that the empirical conditions of income are satisfied for realization of this result. Thus, we could ascertain empirical and theoretical validity of income comparison as explanation for the distributive gap between income and class identification.