To provide a hydrophilizing agent which can clean the surface of a base material, at the same time enables a hydrophilic particle to be adsorbed to the surface of the base material so as to maintain the hydrophilizing effect for a long time, and can be removed by dry wiping without washing with water.

The hydrophilizing agent is prepared by adding a solid particle having a particle size of 0.5 micron or more to a liquid colloidal suspension of a hydrophilic particle having a particle size of 0.050-0.5 micron, and is dry- wiped after coating.