Abstract: A device for applying a predetermined quantity of liquid to a surface, the liquid being contained in a breakable ampule which is substantially cylindrical and enclosed in a flexible and resistant casing closed at one end with an absorbent material, wherein the device comprises a tubular body open at one end, accommodating the ampule and comprising at least two flexible blades formed in its wall, placed substantially opposite each other, each of these blades having at least one tappet facing inward and offset longitudinally with respect to the corresponding tappet of the other blade.