The present is a hydrophilic polymer microparticle, which has a DW/DA ratio of 2.0 or less, the DW representing a particle diameter of the hydrophilic polymer microparticle dispersed in water, the DA representing a particle diameter of the hydrophilic polymer microparticle dispersed in acetone, each of the particle diameters measured by a particle size distribution analyzer after the hydrophilic polymer microparticle is dispersed in water or acetone, subjected to irradiation with ultrasonic waves for 15 minutes, and allowed to stand at a temperature of 25° C. for 240 hours for equilibration; and has a contact angle with water of 70° or less, the contact angle measured using a contact angle measurement apparatus at a temperature of 25° C. by forming a droplet of pure water on a single layer of the hydrophilic polymer microparticles arranged with no space therebetween.