To provide an inner periphery polishing method capable of polishing a central opening hole of a disk-like substrate at extremely good precision.

This method includes a step (S103) for inserting a brush in an opening hole of a disc-like substrate at its center, a step (S105) for affixing one end and the other end of the brush to a pair of rotary shafts coaxially provided at a position separated to each other, a step (S107) for pulling one end and/or the other end of the brush and providing a tensile force in an axial core direction to a core of the brush, and a step (S108) for rotating one end and the other end of the brush and polishing the disc-like substrate while the tensile force is provided.