To provide a stainproof coating agent composition for wall paper excellent in a low gloss property, a stainproof property, blocking resistance, application workability (performance capable of suppressing occurrence of float, separation and joint gap).

The stainproof coating agent composition for wall paper comprises (A) an aqueous dispersion of polymer particles obtained by radically polymerizing an ethylenic unsaturated monomer and having a refractive index of ≤1.50 when the aqueous dispersion is processed into a test piece for measurement of refractive index and refractive index of the test piece is measured according to JIS K7105 by Abbe refractometer, (C) wax and (D) an inorganic filler or the stainproof coating agent composition for wall paper comprises (A) the aqueous dispersion, (B) an aqueous solution of a polymer obtained by radically polymerizing an ethylenic unsaturated monomer and having ≤1.50 refractive index, 25-200 acid value and 10,000-100,000 number-average molecular weight and (C) wax and (D) an inorganic filler.