According to one embodiment, a supercritical drying method for a semiconductor substrate, comprises introducing the semiconductor substrate into a chamber in a state, a surface of the semiconductor substrate being wet with alcohol, substituting the alcohol on the semiconductor substrate with a supercritical fluid of carbon dioxide by impregnating the semiconductor substrate to the supercritical fluid in the chamber, and discharging the supercritical fluid and the alcohol from the chamber and reducing a pressure inside the chamber. The method further comprises performing a baking treatment by supplying an oxygen gas or an ozone gas to the chamber after the reduction of the pressure inside the chamber.