In a casting sand reclamation system and a casting sand reclamation method, an appropriate reclamation process is performed according to the properties of casting sand to improve the reclamation accuracy and the reclamation yield. Capacitance measuring devices 70 and 71 that measure the capacitance of casting sand 1 (recovered sand 1a or reclamation sand 1b) are arranged on an upstream side and a downstream side of a batch-type polishing device 7, and feedback control is performed based on the measurement results of the capacitances by these capacitance measuring devices 70 and 71. A sorting device 10 sorts the recovered sand 1a polished by the polishing device 7 into a sand grain component (reclamation sand) and a fine grain component (containing a binder), and has a capacity N times that of the polishing device 7. A control device 80 performs feedback control based on capacitance RU of the recovered sand 1a measured for each polishing process on an upstream side of the polishing device 7, and an average value of N capacitances RD of the reclamation sand 1b measured for each polishing process on a downstream side of the sorting device 10.