To provide a washing method and device using carbon dioxide capable of washing at a high operation rate by avoiding formation of dry ice and damage to a wash even if pressure within a drum is abruptly lowered after the end of washing using liquid carbon dioxide or critical carbon dioxide.

The washing method includes a washing process in which the wash 12 and the liquid carbon dioxide or supercritical carbon dioxide as a washing solvent are introduced into the drum 6, and a process for taking out the wash 12 from the drum 6 after substituting an inert gas for the washing solvent in the drum 6.