Print hammers in a printing head of a dot line printer for printing with an ink ribbon multiple dot lines in a single shuttling direction and for providing a character line by the combination of the multiple dot lines in accordance with reciprocal motions of the print head while feeding a printing sheet in a line to line direction include hammer springs and printing pins provided at the free tip end portions of the springs. The printing pins are positioned offset from one another in the shuttling direction to thus perform multiple dot line printings in the single shuttling motion. Each of the printing pins has a printing pin surface in abutment with the printing sheet through the ink ribbon. The printing pin surface has a polygonal shape defined by a combination of ridge lines. All ridge lines extend obliquely with respect to the shuttling direction for facilitating grinding of the printing pins.