To obtain a surface modifying agent for a wall paper, capable of clearing various problems existing at the surface part of the wall paper without adopting a conventional film laminate processing.

This surface modifying agent for a wall paper contains 2 components of at least one kind each selected from (A) a synthetic resin having ≥50°C softening point and (B) a silicone resin or a fluorine resin as indispensable components, or 3 components of at least one kind each selected from (A) a synthetic resin having ≥50°C softening point and (B) a silicone resin or a fluorine resin, and (C) silicon dioxide and/or a cross-linking agent as indispensable components.