To obtain a stainproofing protectant that can simply form a coating film that can reduce the adhesion of stains, prevent the fixation of stains, and retain such effects for a long term on a hard surface or a hard surface made hydrophobic, which protectant contatns a water-soluble adsorbent polymer.

This protectant comprises 0.001-50.0 wt.% water-soluble adsorbent polymer and, optionally, adjuvants such as a solvent, a thickener, an antiseptic, an antioxidant, and an ultraviolet absorber. When the protectant is applied to a hard surface, it can form a coating film exhibiting stainproofness. When a coating agent which forms a hydrophobic surface, such as a wax, a silicone, an acrylic resin, or a fluoroplastic, is used as the undercoat for the protectant, the durability of stainproofness can be improved. The water-soluble adsorbent polymer is exemplified by a water-soluble polysaccharide or a cationized water- soluble polymer such as a cationized water-soluble polysaccharide such as cationized cellulose or a cationized synthetic polymer such as a dimethyldiallylammonium chloride/acrylamide copolymer.