This study is to analyze how Foucquet`s private wealth was related to the public financial administration during the mid-seventeenth century in France. With heavy military expenses each year creating a huge deficit due to the war with Spain and the military policy followed by Mazarin, Foucquet as a superintendant of finances was obliged to mobilize credit for the monarchy, using his own property as security for loans intended directly or indirectly for the crown. His system had made no distinction between his own and the king`s money, as it made no distinction between public and private interests. The apparently hard-headed business of government rested on continuing efforts at personal seduction, in which Foucquet`s lavish mode of living had its prominent role ; the private vice of luxury had become a political virtue, which helped royal government to continue function. In this way, despite the inadequacies of its fiscal structures and crippling shortage of hard cash, Foucquet allowed the monarchy to pay for the war. Thus, Foucquet illustrates the completeness with which public and private spheres overlapped in the seventeenth-century France. As long as much of what Foucquet had done, while technically illegal, was common practice among financial officials at all levels of the royal administration, the surintendancy of Foucquet clearly revealed the limits and inadequacies of financial system of the absolute monarchy in France. (Yonsei University)