Abstract: A polishing apparatus, includes: a motor; and a controlling unit configured to control the motor, wherein: a glass substrate is polished by causing the controlling unit to control a driving of the motor; and the controlling unit executes a controlling operation for controlling a polishing of the glass substrate, based on an electric power or an electric energy required for the driving of the motor.

Abstract: An abrasion brush in which a width of each of bristle implanting portions is 1.1 to 2.2 times a stack width of stacked glass substrates (a thickness of each of the glass substrates when the glass substrates are stacked without using a spacer. or a sum of the thickness of the glass substrates and a spacer when the glass substrates are stacked using spacers) is used for an inner periphery end surface polishing of a magnetic recording medium glass substrate. By performing the inner periphery end surface polishing using the abrasion brush, scratches remaining in a chamfering portion of the glass substrate can be removed reliably with a high productivity, and it is possible to provide the magnetic recording medium glass substrate without pit defects in the chamfering portion.

Abstract: A polishing apparatus, includes: a motor; and a controlling unit configured to control the motor, wherein: a glass substrate is polished by causing the controlling unit to control a driving of the motor; and the controlling unit executes a controlling operation for controlling a polishing of the glass substrate, based on an electric power or an electric energy required for the driving of the motor.