With the use of hair rollers whose bodies each have an outer longitudinal section bordering on both sides on a central, flexible longitudinal section remaining in the curved state, (previously) permed or water-waved parts of a strand of hair are spirally wound, starting with the ends, first on one outer longitudinal section and then progressively on the central longitudinal section, while finally the previously untreated part of the hair (hairline) is wound substantially around the other outer longitudinal section. Thereafter one longitudinal section is bent approximately at right angles to the other in such a way that one longitudinal section and a part of the central one with the previously treated hair stands substantially vertically upwards from the head. Intensive-action perming or water-waving liquid is then applied only to the previously untreated hair (hairline) substantially wound on the other longitudinal section. In a roller (1) especially suitable for implementing the process, the roller body has a first longitudinal section (2) made of a substantially rigid material on which is arranged or with which engages a securing component (9, 10). One end of the first longitudinal section (2) is connected to a second flexible longitudinal section (3) consisting of a flexible body (5) of visco-elastic plastic arranged about a wire core (4).