PURPOSE: To restrain abrasion of a guide plate by minimizing a force of a print wire to rub a guide hole and reduce damage by lowering a bending stress which works on the print wire.

CONSTITUTION: A base end of a print wire 20 is fixed to a rocking arm 10 and is inserted into guide holes of a plurality of guide plates 36, 37, 38, and 39 so as to converge to a print medium. Almost along a curvature line of the print wire 20 connecting the guide hole of the head end guide plate 36 and an arm side fixed end, the guide holes are formed in the intermediate guide plates 37, 38, and 39. The intermediate guide plate 39 nearest the arm 10 is formed to be thicker than other guide plates. Further, each guide hole is formed so as to become smaller in sequence from the intermediate guide plate 39 nearest the arm 10 to the head end guide plate 36.