Abstract: An object of the present invention is to provide a makeup brush bristle material and a makeup brush bristle material assembly, both made of synthetic resin, as well as a makeup brush using such bristle material or bristle material assembly, all suitable for applying both powder cosmetics and liquid cosmetics, or more specifically, offering good uptake and release properties with respect to powder or liquid cosmetics. As a solution, a makeup brush bristle material is provided that comprises S-twisted or Z-twisted core-sheath complex monofilaments whose core part is constituted by synthetic resin A and sheath part is constituted by synthetic resin B that differs in type from synthetic resin A, characterized in that the cross-section of the core-sheath complex monofilaments in the direction orthogonal to the axis of fiber has a cocoon shape.

Abstract: An object is to provide a makeup brush bristle material and a makeup brush bristle material assembly, both made of synthetic resin, as well as a makeup brush using such bristle material or bristle material assembly, all offering good uptake and release properties with respect to powder or liquid cosmetics. As a solution, a makeup brush bristle material constituted by S-twisted or Z-twisted synthetic resin monofilaments, characterized in that the cross-section of the monofilaments in the direction orthogonal to the axis of fiber has a cocoon shape, is provided.