An improved electrode headset is provided for the acquisition of electroencephalographic (EEG) brain signals detected at the scalp of a human subject. The headset includes an elastic fabric cap having a chinstrap, which cap is fitted closely to the scalp. The cap has openings at those selected locations on the scalp to which removable and disposable electrodes are to be removably connected to the scalp. A positioning unit, of a generally flat and flexible plastic material, is attachable to the cap by corresponding hook-and-loop fasteners on the outer surface of the cap and the inner surface of the positioning unit. The positioning unit has a base portion and two opposite leg portions, each with slits. Flat beams are adjustably connected through the slits to the leg portions and base portion. Each beam carries a screw member which adjustably applies pressure to electrode holders and a flexible electrode extractor strap to which the electrode holder is attached. Each electrode holder is snap fastened to an electrode positioned within a cap opening.