The present invention provides a means by which it is possible to sufficiently suppress an organic residue while favorably decreasing a ceria residue on a polished object to be polished obtained after being polished using a polishing composition containing ceria.
The present invention relates to a composition for surface treatment, which is for a surface treatment of a polished object to be polished obtained after being polished using a polishing composition containing ceria, contains a carboxy group-containing (co)polymer having a structural unit derived from a monomer having a carboxy group or a salt group of the carboxy group, a SOx or NOy partial structure-containing compound having a partial structure represented by SOx or NOy (where x and y each independently denote a real number 1 to 5), and a dispersing medium, and has a pH of 1 or more and 8 or less.