To provide a method for classifying granular hydrophilic polymers and a sieve by which the polymers having minute diameters are efficiently classified, and the inherent separative power of the sieve is exhibited.

In the classifying method of granular hydrophilic polymers, the granular hydrophilic polymer is kept at 30-100°C, the contact angle to water of the contact surfaces between the polymer and sieve other than the screen net surfaces is kept at ≥60°, and the material has ≥70°C heat distortion temp. In the sieve, the contact angle to water of the contact surfaces between the grain and sieve except the screen net surfaces is controlled to ≥60°, and the material of the sieve has ≥70°C heat distortion temp.