Surface treatment

(57) It is the method of processing a summary base material, and carbon dioxide and the pressurization fluid containing a surface treatment ingredient are contacted in the surface of this base material, it goes together into pressurization fluid, this surface treatment ingredient contacts this surface, and this surface treatment ingredient includes reducing the surface tension of the surface of this base material, and processing a base material. The above-mentioned contact step is preferably performed by immersion, the above-mentioned fluid is a liquid or a supercritical fluid preferably, the above-mentioned base material is metal or a textile base material preferably, and the above-mentioned surface treatment ingredient is full オロアクリ rate polymer preferably.