<p>[PROBLEMS] To provide a hydrophilizing agent excellent in hydrophilization performance and unsusceptibility to fouling. [MEANS FOR SOLVING PROBLEMS] The hydrophilizing agent, when applied to a solid surface, reduces the contact angle of water with the solid surface. It is characterized by containing a (C<SUB>2-3</SUB>)alkylene oxide adduct of acetylene glycol in which the average number of moles of the alkylene oxide which has added per molecule of acetylene glycol is 3.5-50. The hydrophilizing agent preferably further contains a carboxylic acid polymer.</p>
