PURPOSE: To easily adjust the relative position of a platen and a print wheel while preventing the generation of positional shift, by simple constitution such that the axis position of a shaft, around which a carriage is freely slidable, is changed by a freely revolvable eccentric part.

CONSTITUTION: When a first lever 28 is revolved, an eccentric bearing 27 is revolved and the axis position of a shaft body 29 around which a carriage main body 26 is freely slidable to move the main body 26 up and down as well as left and right. In addition the rear position of the main body 26 is similarily changed by revolving a second lever 31. By this simple constitution, the relative position of a platen and a print wheel can be easily adjusted and, because parts directly contacted without using friction force in engagement are not used, the generation of positional shift is prevented.