This study used the APC model to estimate the age effect, period effect, and cohort effect shown in the Gini coefficients of before-tax income, after-tax income, and consumption. The main results are as follows. First, inequality in before-tax income has steadily increased since the 1990s, but inequality in after-tax income has increased only moderately, and inequality in consumption has not worsened until recently. Second, the difference between before-tax income and after-tax income inequality indicates the effects of income redistribution, which contributed to reducing inequality in after-tax income by greatly weakening the age effects. Third, the reason why inequality in consumption was so stable is because the age effects were very weak and the cohort effects offset it. The cohort effects observed in consumption inequality means that the consumption inequality of subsequent generations was smaller than that of the preceding generations. In a sense, Korea is becoming more equal when it comes to consumption. Fourth, another reason why inequality in consumptions was very stable was the two-earners’ income effect. The number of dual-income households has been steadily increasing, and their consumptions did not become significantly unequal even as they became older. Furthermore, they were less affected by recession, and not significantly more unequal than for the predecessors. In other words, two-earners’ households have been effectively provided insurance against income risks. In Korean society where has changed rapidly due to high economic growth in a short period of time, age effects, period effects, and cohort effects account for a large part of trends in income and consumption inequality.