A device for treating human keratin materials, in particular with the aid of an electric current. The device includes a reservoir containing an in particular cosmetic or dermatological composition to be applied to the keratin materials, a unit for dispensing the composition contained in the reservoir, in particular a pump, and an end fitting for applying the composition contained in the reservoir, comprising at least one applying member and in particular a plurality of applying members. The applying member is supplied with the composition from the reservoir by the dispensing unit, the composition passing through an intermediate chamber for storing the composition located in the end fitting, the intermediate chamber being at least partially defined by an elastically deformable wall.