To sort constituent materials in a mixture with higher purity, in an electrostatic sorting apparatus which sorts and separates the mixture into constituent materials in an electrostatic field by utilizing difference in orientation of static electricity and easiness of charging between the constituent materials of the mixture.

The electrostatic sorting apparatus has a pair of positive and negative electrodes 20 and 21 and causes charged target materials to fall between the electrodes 20 and 21 to deflect positively charged plastics on the side of the negative electrode and negatively charged plastics to the side of the positive electrode so as to sort the materials. The charged materials tend to aggregate to form clustered lumps. The materials in the form of lumps sometimes escape the deflection during passing through between the electrodes 20 and 21 because of their weights, resulting in a cause of deterioration of the sorting precision. Therefore, the lumps are eliminated before the materials pass through between the electrodes 20 and 21.