According to an embodiment, a supercritical drying method includes: introducing a semiconductor substrate of which a surface is wet with a supercritical displacement solvent into a chamber; supplying a first supercritical fluid being based on first carbon dioxide to the chamber; supplying a second supercritical fluid which is based on second carbon dioxide to the chamber, after the supplying of the first supercritical fluid; and lowering an inside pressure of the chamber to gasify the second supercritical fluid and to discharge the gasified second supercritical fluid from the chamber. The first carbon dioxide is generated by recovering and recycling the carbon dioxide discharged from the chamber. The second carbon dioxide contains no supercritical displacement solvent or contains the supercritical displacement solvent in a concentration lower than that in the first carbon dioxide.