To provide a simple-structured mascara applicator brush which allows a user to keep her hands off from her face in applying a mascara and to apply a sufficient amount of the mascara to eyelashes, and to sequentially comb her eyelashes from the inner corner of the eye to the outer corner and vice versa to made them curly.

A brush part of this mascara applicator brush is externally shaped like a frustum of a cone and is provided with one or more cut and sunken parts which are twisted and inclined toward the central axis of the brush part.