Abstract: Relates to a pocket-type writing instrument, employing an extruded rod-like writing element composed of a homogeneous thermoplastic composition having a formation of longitudinally extending ink-conducting channels around an axial channel, one end of said element constituting the writing point and the other being in contact with a body of ink, usually carried in an absorbent material contained in the barrel of the pen. Provides novel means for preventing axial displacement of the writing element without damage to or constriction of the ink channels therein and without the use of wire pins which may interfere with the ease of handling of the instrument.