To provide polyvinyllactam cross-linked product fine particles which improves a problem that polyvinyllactam product particles having an average particle diameter of >1μm are liable to adhere to each other due to their hygroscopicity and can hardly be crushed into the fine particles, because of having a large cohesive force, and to provide a method for producing the same.

The highly cohesive / adhesive polyvinyllactam cross-linked product can be crushed into a fine particle diameter with a crusher without reaggregating the particles. The polyvinyllactam cross-linked fine particles have an average particle diameter of ≤1μm. A polyvinyllactam cross-linked product fine particle dispersion is obtained by dispersing the polyvinyllactam cross-linked product fine particles in a dispersant. The method for producing the polyvinyllactam cross-linked product fine particles comprises mechanically crushing the polyvinyllactam cross-linked fine particles have an average particle diameter of >1μm into an average particle diameter of ≤1μm.