A method of cleaning a plasma processing apparatus includes: disposing a first dummy substrate at a first position with respect to a stage inside a chamber and performing a first dry cleaning process inside the chamber; and disposing a second dummy substrate at a second position with respect to the stage inside the chamber and performing a second dry cleaning process inside the chamber, wherein each of a center of the first position and a center of the second position is located at a different position from a center of the stage in a plan view, and wherein the first position and the second position are different from each other in a plan view.