A method for filling concave portions of a concavo-convex pattern by which the concave portions of the concavo-convex pattern can be filled to flatten the surface with reliability, and a method for manufacturing a magnetic recording medium by which a magnetic recording medium having a magnetic recording layer of concavo-convex pattern with a sufficiently flat surface can be manufactured efficiently. A filler for filling the concave portions is deposited over the surface of an object to be processed, the object being provided with a concavo-convex pattern. A cladding is further deposited over the filler. Then, an excess part of the filler and the cladding above the surface of the object are removed for flattening, by using a dry etching method having a lower etching rate to the cladding than to the filler.