PURPOSE: To raise productivity, by a method wherein plural guide holes through which printing wires are inserted are provided to a guide member and those guide holes are formed taperingly from the basic end side to the top end side.

CONSTITUTION: The top end part 51 of the guide hole 50 of a guide member 43 is open upward and therefore, a printing wire 32 can be easily inserted. A guide member 42 has a guide hole 52 formed taperingly downward. The top end part of this guide hole 52 has a diameter larger than that of the bottom end part of the guide hole 50. Thereby, the printing wire 32 inserted through the guide hole 50 can be smoothly inserted into the guide hole 52. Guide holes 54, 55 are formed in guide members 37, 38 in the same way, too and therefore, the printing wire 32 can be smoothly guided from the guide hole 54 to the guide hole 55 to be inserted.