The present invention relates to a device for applying a fluid or pasty product to keratin fibers, comprising an elongate core (1) extending on a longitudinal axis XX. Advantageously, the device additionally comprises at least one pliant and flexible rod (2), which is oriented longitudinally and is embedded, at least at a first and a second point, on said longitudinal core (1), so as to form at least one zone of flexion perpendicular to the longitudinal axis XX; it is made in one piece and preferably from a plastic material.