A recycling method of slurry for use in wafer polishing for reusing slurry used in a polishing process of semiconductor wafer, comprises the steps of: adding a dispersant to a recovered used-slurry to inhibit aggregation of the slurry; breaking up aggregates in such a manner that the whole of the used slurry, subjected to the dispersant addition step, is passed through a shearing force imparting device to impart shearing force to the aggregates contained in the slurry by the shearing force imparting device, thereby breaking up the aggregates; and removing foreign substances in the slurry subjected to the aggregate breakup step, by means of a foreign substances removing device. According to the method, a large amount of used-slurry can be processed in a short time.