METHOD FOR PRODUCING MAGNETIC DISK SUBSTRATE

PROBLEM TO BE SOLVED: To provide a method for producing a magnetic disk substrate, the method enabling reduction of scratch caused after a coarse polishing step and scratch and protrusive defect caused after a final polishing step.SOLUTION: A production method includes the steps of: (1) polishing a polishing target surface of a polish object substrate, with a polishing liquid composition A containing alumina particulates and water; (2) rinsing the substrate obtained in the step 1; (3) polishing a polishing target surface of the substrate obtained in the step 2, with a polishing liquid composition B containing silica particulates and water; (4) cleaning the substrate obtained in the step 3; and (5) polishing the substrate obtained in the step 4, with a polishing liquid composition C containing silica particulates and water. Further, the steps 1 through 3 are performed on the same polishing machine; the step 5 is performed on a polishing machine different from the polishing machine; and the polishing liquid composition A further contains (i) an organic phosphonic acid chelate compound, (ii) high-molecule anion surface active agent having a molecular weight of 300-300000, and/or (iii) an organic phosphate ester.