A managing system for managing slurry, which is supplied to a wire saw. Slurry is prepared in a preparing tank and sent to the wire saw and used to cut workpieces. After usage for cutting workpieces, the slurry is sent to a separating apparatus from the wire saw. The separating apparatus separates impurities from the used slurry to recover a mixture of recyclable dispersing liquid and abrasive grains from the used slurry. The recovered mixture is returned to the preparing tank. The recovered mixture is mixed with fresh abrasive grains and dispersing liquid in the preparing tank to prepare slurry. The property (specific gravity and viscosity) of the slurry in the preparing tank is detected. The amount of fresh abrasive grains and dispersing liquid supplied to the preparing tank is adjusted in accordance with the detection results. Accordingly, slurry having properties that are optimal for the cutting of workpieces is prepared.