Polishing brush and polishing method

A polishing brush comprising:

• a grinding element bundle formed of a plurality of wire-shaped grinding elements;
• and
• a rod-shaped member, wherein
• when a direction along an axis of the rod-shaped member is an axial direction, a direction orthogonal to the axis is a radial direction, a direction intersecting the axial direction and the radial direction is an inclination direction, and one side of the axial direction is a front side and the other side is a back side,
• the rod-shaped member has a holding hole at a front portion to hold the grinding element bundle,
• the holding hole has a bottom face, a sleeve-shaped peripheral wall extending from the bottom face in the inclination direction, and an opening facing one direction of the radial direction,
• the grinding element bundle has a seated portion seated in the holding hole, and a protruding portion protruding from the opening of the holding hole in the inclination direction,
• an inclination angle at which a hole axis of the holding hole intersects the axis is 45° or less, and
• a tip end of the protruding portion is located outside of the rod-shaped member when viewed from the axial direction.