PURPOSE: To operate smoothly by a pen carriage wherein runout of a pen holder of the pen carriage in a plotter can be stopped with a simple structure.

CONSTITUTION: A piece of sliding guide 13 is provided on a carriage base 11 of a pen carriage 10. Guide grooves are provided on 3 side faces of the sliding guide 1.3 in up and down directions. On a pen holder base 21 of a pen holder 20, a recess 22 to be set on the sliding guide 13 is provided. 1 guide groove is formed also on the side of the recess 22 at a part where the two are to be connected. In a manner straddling both of the guide grooves, a ball to be held by a holding device of a slide bearing 27 is engaged and assembled, so that precise plotting is possible without adjusting operation. Accordingly, highly precise plotting can be performed with simple assembly and a small number of parts.