Glass substrate for magnetic recording medium, production method thereof, and magnetic recording medium using the substrate

The present invention provides a production method of a glass substrate for magnetic recording medium having an inner diameter and an outer diameter comprising an edge polishing step of a glass substrate. In one embodiment of the production method, it has the edge polishing step in which the inner or outer diameter of the glass substrate is chucked, in a single disk process, and the edge surface of the outer or inner diametral side of the glass substrate is polished using a polishing tape or a grindstone. Further, the present invention relates to a magnetic recording medium using the glass substrate. The production method of a glass substrate of the present invention can perform a polishing of edge surface in a high-quality without generating a defect on the surface of the glass substrate. The present invention can provide a superior magnetic recording medium by using the glass substrate.