PURPOSE: To form the thin hydrophilic layer on a surface of an object by impregnating the object manufactured from a non-hydrophilic (meth)acrylate polymer in specified heated strong acid.

CONSTITUTION: The method forms a thin hydrophilic layer on a surface of an object manufactured from a non-hydrophilic polymer containing a (meth) acrylate and/or nitrile unit through hydrolysis by means of specified heated strong acid, and the object is immersed in a heated strong acid containing electrolyte not reacting with only the polymer and having been dissolved in advance. According to above, a dense and optionally thin and stiff hydrophilic layer is provided. The method is suitable especially for the hydrophilicity for in-eye lens, contact lens, or its support member, and a surgical tool (e.g. tip of surgical extractor) made of a poly(methyl methacrylate).