In an eyeless sewing needle, a periphery of an axial hole at the base end 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 of the axial hole towards the needlepoint. 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.