A free-ink type writing instrument having a temporary ink collector having a sectionally combed configuration, between an ink tank chamber and an writing tip and inside the front barrel, wherein all or part of the gaps between neighboring combed teeth for retaining ink in the temporary ink collector are set equal to 0.15 mm or smaller, and the ink tank is charged with an ink having a surface tension equal to 30 mN/m or lower at 25° C.