A processing method for processing a substrate includes: a first arrangement step of mounting, on a stage provided in a processing container to mount the substrate on the stage, a plate-shaped protective member which is prepared in advance at a location in the processing container different from a location on the stage and which is configured to protect an upper surface of the stage; an adjustment step of adjusting a distance between the stage and an annular cover member provided above an edge portion of the stage to a second distance different from a first distance between the stage and the cover member when the substrate is processed; and a pretreatment step of performing a pretreatment in the processing container to change a state in the processing container to a predetermined state, wherein the protective member has a thickness different from a thickness of the substrate.