PROBLEM TO BE SOLVED: To provide a surface treatment method for flattening the surface of a viscous material, when the viscous material is filled into a container, which is a surface treatment method for shaping so as to have a smooth and flat surface shape without preparing complex accessories, and to provide a device therefor.SOLUTION: In a surface treatment method of a filled viscous material, which is a surface treatment method for shaping flatly the surface shape of the viscous material by pressing the lower end surface of a pressure body onto the surface of the viscous material, before pressing the pressure body onto the surface of the viscous material, a liquid film is formed in the noncontact state to the pressure body, on a region to be brought into contact with the viscous material of the pressure body.
