In this chapter, we measure Foster–Greer–Thorbecke (FGT) poverty indices for children in elementary, junior high, and high schools across Japan’s major metropolitan areas and other regions. Using data from the National Survey of Family Income and Expenditure, we calculated the indices from both equivalent consumption and private supplementary educational expenditures over four survey periods from 1999 to 2014. We found consistently higher poverty indices in non-metropolitan areas across both metrics. Although changes in FGT indices based on equivalent consumption expenditure had minimal regional disparities, the squared poverty gap for private supplementary educational expenditure varied significantly between regions. Notably, from 2009 to 2014, the FGT indices rose substantially in non-metropolitan areas, but declined in major metropolitan areas when excluding distributional effects.