Based on ‘Household Income Trends’ in 1990~2016, this study analyzes how wealth inequality has increased in Korean society. According to the analysis, cohorts born in the 1930s~40s and the 1970s~80s show especially a high level of wealth inequality within generation, which the study argues is due to the real estate boom in the 1970s and the 1980s. When those born in the 1930s~40s were in their 40s, the price of property skyrocketed, and this led to enormous wealth inequality within this cohort; between those who benefited from the boom and those who could not. Through inter-generational wealth transfers, this wealth inequality within generation was reproduced in their children’s cohort born in or after the 1970s. The study points out the possibility that this inter-generational reproduction of wealth inequality could increase resistance to the strengthening of the public welfare system.