Provide is a direct liquid type writing-brush pen that is equipped with a valve mechanism; and with which the ink tube is of replaceable cartridge type, and the writing brush tip is always impregnated with an appropriate amount of ink while the ink leakage being suppressed, whereby an excellent feeling of writing can be always given. A direct liquid type writing-brush pen, including a barrel, which holds a writing brush tip unit at the distal end part thereof; an ink cartridge, which is slidably and detachably fitted into the barrel from the basal end side thereof; a cap, which covers the writing brush tip unit; and a stopper, which is fitted to the basal end part of the barrel to slidably support the basal end part of the ink cartridge, which is protruded from the basal end side of the barrel, wherein, in the distal end part of the ink cartridge, a valve mechanism, which accommodates a valve core in a valve seat, is incorporated; in the valve seat, the distal end part of the valve core is removably connected to the basal end part of a relay core, which constitutes the writing brush tip unit; and on the circumferential face of a smaller diameter part of the valve seat, a sealing strip is formed.