To provide a method of preparing a polyimide resin that can industrially advantageously prepare a polyimide resin which has a very high utility value as electric/electronic materials, is excellent in heat resistance and fabricability and has a stable quality without using an organic solvent.

In the preparation method of the polyimide resin, a tetracarboxylic dianhydride and a diamine are kneaded using a kneader without any solvent and reacted through shear heating. Here, the tetracarboxylic dianhydride and the diamine are both in solid states and preferably have average particle sizes of ≤30 μm.