Abstract: A method for manufacturing a glass substrate for a magnetic disk comprises mirror surface polishing and cleaning of a glass substrate, wherein polishing agent of which the principal component is rare-earth oxide with content of fluorine 5% by weight or less, is supplied to the glass substrate, the surface of the glass substrate is subjected to mirror surface polishing by relatively moving the polishing cloth and the glass substrate, then this glass substrate is brought into contact with a cleaning solution including ascorbic acid, fluorine ion, and sulfuric acid of 3% by weight or more, and the polishing agent is dissolved and removed. The concentration of the ascorbic acid included in the cleaning solution is 0.1% by weight or more, and the content of the fluorine ion is 1 ppm to 40 ppm. At least a magnetic layer is formed on the obtained glass substrate to manufacture a magnetic disk.

Abstract: A method for manufacturing a glass substrate for a magnetic disk comprises mirror surface polishing and cleaning of a glass substrate, wherein polishing agent of which the principal component is rare-earth oxide with content of fluorine 5% by weight or less, is supplied to the glass substrate, the surface of the glass substrate is subjected to mirror surface polishing by relatively moving the polishing cloth and the glass substrate, then this glass substrate is brought into contact with a cleaning solution including ascorbic acid, fluorine ion, and sulfuric acid of 3% by weight or more, and the polishing agent is dissolved and removed. The concentration of the ascorbic acid included in the cleaning solution is 0.1% by weight or more, and the content of the fluorine ion is 1 ppm to 40 ppm. At least a magnetic layer is formed on the obtained glass substrate to manufacture a magnetic disk.