Abstract: Brush-pen of round and flat hair and permanent liquid ink of adjustable flow for drawing and writing, including a container on the upper part of the outer body of the ferrule. This container is provided with a cap with a controlling device, into which the desired liquid ink is introduced. The ink goes through an orifice of the upper part of an outer cylinder of the ferrule and through a winged guide cap of an inner cylinder of the ferrule. The inner cylinder contains a piston provided with a pressure shaft controlled by the controlling device of the cap so as to provide adjustment of the passage of ink through a hollow needle of the ferrule. This maintains a constant flow of ink to the hair (brush) tip in the desired amount, doing without the need of inkpots. The alternating downwards and upwards movement of the piston keeps the channel constantly clean.