The aim of this study is to investigate the budgets of public libraries from a financial point of view. We analyzed historical data of nationwide public library budgets. We especially examined it from three aspects, the total budget, funding sources, purposes of budgets. We also used data of local government budgets and budgets for social education to compare the library budgets. The results showed that the trend of local government budgets had strong influence over library budgets. The trend of library budgets bore a striking resemblance to budgets for social education. Capital expenditure of libraries had drastically decreased from late 1990s in line with the burst of economic bubble.