An apparatus for drying a wafer, includes: a drying chamber; a supercritical fluid supply module configured to supply supercritical fluid to the drying chamber; a main exhaust line connected to the drying chamber and in which a main valve is installed; and an auxiliary exhaust unit connected to the main exhaust line. The auxiliary exhaust unit includes: an auxiliary exhaust line connected to the main exhaust line and configured to exhaust the supercritical fluid from the drying chamber when the main valve is closed; a negative pressure tank installed in the auxiliary exhaust line; a first valve, installed in the auxiliary exhaust line, that is configured to be opened when the main valve is closed; and a second valve, installed in the auxiliary exhaust line, that is configured to be opened in conjunction with the first valve.