Abstract: A composite writing instrument comprising a writing instrument mechanism having a plurality of refills and a rod-like delivery mechanism, the composite writing instrument comprising middle shaft provided between a front shaft and a rear shaft, return springs having one end terminated at the middle shaft to urge the refills, respectively, backward; sliding cams mounted at rear portions of the refills and terminated at the other ends of the return springs to be urged backward, a cam body having at a front portion a cam operating portion which presses the rear end of either of the sliding cams to selectively advance the refills; a guide tube rotatably engaging the cam body and having a guide groove in the axial direction; a slider formed in the guide tube holding a rod-like article and being slidable in the axial direction along the guide groove of the guide tube, the cam body being provided with an engaging portion which engages the middle shaft so as to be slidable in the direction of the front shaft and be ro