In an eyeless sewing needle (10), a periphery of an axial hole at the base end (lla) is heated to make a fibrous structure be a granular structure without directionality, and at least a part of a heat-affected zone made between the fibrous structure and the granular structure due to the heating is within a range that is three times the diameter of the sewing needle and that extends from an effective base (12c) of the axial hole (12) towards the needlepoint (14). This allows provision of a flexible sewing needle so that the hole periphery can be processed while keeping a hard state at the position of the needlepoint slightly away from the axial hole.