A scalp protector for the application of free-flowing hair treatment agents, in which according to the invention a comb-like first bundle of tines (1) protruding from a first web (3) having tines extending essentially parallel to one another is provided, wherein a cover element which adjustably constricts the free space between the tines is provided. The invention therefore represents a mechanical barrier, which is inserted into the hair at the point to be treated and remains there during the duration of the treatment. Since according to the invention a cover element, which adjustably constricts the free space between the teeth, is provided, the cover element can primarily be selected so that the free space is enlarged and easy insertion into the hair is possible. In the further proceedings, the cover element can be adjusted so that the free space is constricted and the scalp is completely covered down to the regions in which the individual hairs aligned in the free space between the tines pass through. Furthermore, different embodiments of the cover element are proposed.