Gakushuin Economic　Papers ．　 VoL33 ，　 No3，4 ，　 January　1997 The Over－Skilled　Japanese：Changes in Eamings　Inequality　in　Japan

The income distribution has been changing in Japan since the 1980s ． It was said in the past that income distribution was highly equa1孟sed in Japan ， compared to other countries ． For example ， in the 1976 0ECD Economic Outlook ， Malcom Sawyer reported that Japan was an equa1 society in terms of income distribution ． Sawyer compared the income distribution statistics of ten advanced countries and concluded that Japan was the fbremost country in terms of income equality ． His results were mainly based on the statistics of the late 1960s and early 1970s ， These periods were coincide with the rapid growth era in Japan when various measures of income differences diminished sha叩ly． After the end of the rapid growth period and the twice oil shocks ， however ， income inequality has been gradually increasing in Japan ． According to the Fami豆y Income and Expenditure Survey by the Bureau of Statistics ， the shares of annual gross income have increased the gap between top and bottom quintiles among all households since the late 1970s． The increase in income inequa夏量ty can be confirmed from a different statistical source ． Using the Survey on lncome and Distribution by the Ministry of Health and Welfare ， which is the background data fbr social security policies ， we can distinguish the primary income ， wh童ch is the sum of all private income， and the redistributed income including all the net benefits of social insurance ， transf6r net of taxes ， and in－ kind income of medical benefits ． Even if we consider these two incomes respectively ， we can still find the modest increase in income inequality fbr the primary and redistributed incomes respectively．（See Ohtake 1994fbr detailed survey fbr distribution of income and wealth in Japan in the 1980s） Among total household income sources ， the large component is shared by the wage income ， or eamings ． Earnings孟nequality declined in the rapid growth period ， but it increased steadily in the 1980s， implying that the increase in earnings inequaiity played a role in enlarging income inequality among households