Disclosed is a system for dissociating a sheet-shaped cell culture into individual cells. The system, so configured as to minimize the amount of damage to cells when dissociating a sheet-shaped cell culture into individual cells, in one form includes: (i) a reaction unit that dissociates the sheet-shaped cell culture; (ii) a sensor unit that acquires information relating to a particle size distribution of cells inside the reaction unit; and (iii) an analysis unit that computes the particle size distribution of the cells from the information acquired by the sensor unit and determines and outputs a dissociation state.