Patent ID: 8895165

Claim:
A method of manufacturing a magnetic disk glass substrate for use in manufacturing a magnetic disk, comprising: a main surface polishing step of polishing a glass substrate having a pair of main surfaces, wherein, the main surface polishing step comprises (1) main surface polishing one of the main surfaces of the glass substrate so that the one main surface has an arithmetic mean roughness (Ra) required for magnetic recording, and (2) main surface polishing the other main surface of the glass substrate so that the other main surface has a roughness which is higher than the arithmetic mean roughness (Ra) of the one main surface and which is low enough to prevent elution of a component forming the magnetic disk glass substrate and which is not required for the magnetic recording, wherein the arithmetic mean roughness (Ra) of the one main surface is 0.30 nm or less while the roughness of the other main surface falls within a range of 1.5 nm to 5 nm, and wherein the magnetic disk has only on the one main surface a magnetic recording layer.