A kneaded sand property adjusting system comprising: a batch kneading device; a kneaded sand property measuring instrument that measures a property of the kneaded sand being kneaded; a water injection device that injects water into the kneading device; a kneaded sand storage hopper that stores the kneaded sand discharged from the kneading device; a molding device that performs molding by using the kneaded sand discharged from and conveyed from the kneaded sand storage hopper as molding sand; a control device that controls water injection by controlling the water injection device until the property of the kneaded sand in the kneading device meets a kneaded sand target property; a kneaded sand amount measuring instrument (11,12,13,14) that measures the amount of the kneaded sand stored in the kneaded sand storage hopper; and a molding sand property measuring instrument that measures the property of the molding sand to be loaded into the molding device; wherein the control device comprises: a storage unit that stores the batch number of each kneaded batch and the kneaded sand property measured by the kneaded sand property measuring instrument in each kneaded batch in association with each other; a molding sand batch number calculation unit that calculates the batch number of the kneaded batch that corresponds to the molding sand whose property is being measured by the molding sand property measuring instrument on the basis of the amount of the kneaded sand measured by the kneaded sand amount measuring instrument (11,12,13,14); and a correcting unit that associates the molding sand property measured by the molding sand property measuring instrument with the kneaded sand property stored in the storage unit on the basis of the batch number that was calculated and corrects the kneaded sand target property on the basis of the values of the properties. a batch kneading device; a kneaded sand property measuring instrument that measures a property of the kneaded sand being kneaded; a water injection device that injects water into the kneading device; a kneaded sand storage hopper that stores the kneaded sand discharged from the kneading device; a molding device that performs molding by using the kneaded sand discharged from and conveyed from the kneaded sand storage hopper as molding sand; a control device that controls water injection by controlling the water injection device until the property of the kneaded sand in the kneading device meets a kneaded sand target property; a kneaded sand amount measuring instrument (11,12,13,14) that measures the amount of the kneaded sand stored in the kneaded sand storage hopper; and a molding sand property measuring instrument that measures the property of the molding sand to be loaded into the molding device; wherein the control device comprises: a storage unit that stores the batch number of each kneaded batch and the kneaded sand property measured by the kneaded sand property measuring instrument in each kneaded batch in association with each other; a molding sand batch number calculation unit that calculates the batch number of the kneaded batch that corresponds to the molding sand whose property is being measured by the molding sand property measuring instrument on the basis of the amount of the kneaded sand measured by the kneaded sand amount measuring instrument (11,12,13,14); and a correcting unit that associates the molding sand property measured by the molding sand property measuring instrument with the kneaded sand property stored in the storage unit on the basis of the batch number that was calculated and corrects the kneaded sand target property on the basis of the values of the properties. a storage unit that stores the batch number of each kneaded batch and the kneaded sand property measured by the kneaded sand property measuring instrument in each kneaded batch in association with each other; a molding sand batch number calculation unit that calculates the batch number of the kneaded batch that corresponds to the molding sand whose property is being measured by the molding sand property measuring instrument on the basis of the amount of the kneaded sand measured by the kneaded sand amount measuring instrument (11,12,13,14); and a correcting unit that associates the molding sand property measured by the molding sand property measuring instrument with the kneaded sand property stored in the storage unit on the basis of the batch number that was calculated and corrects the kneaded sand target property on the basis of the values of the properties.