In printing heads for a dot line printer, a plurality of which are arranged in line on the reciprocal frame and impact printing wires toward a platen by the driving force of electromagnets excited with the basis of the printing commands, the printing heads for a dot line printer includes electromagnetic actuators including shells which contain and fix cores being wound driving coil around therein and base plates which are attached to the shells in order to close up their opening sides, and forming the tightly closed magnetic loops, and printing springs one ends of which are fixed and supported by supporting portions extended from the base plates, the top ends of which fix armatures at the postion facing to the cores. The printing heads can be unitized, and the close arrangement of the base plates and the armatures can be accomplished by means of direct positioning and fastening of the printing springs to the base plate so that the device can be obtained with excellent maintenance capability as well as small sizes and light weight.