Abstract: A pen changer for use in an X-Y plotter which plots on a paper. The pen changer includes a frame and a shaft supported thereon. The carriage is supported on the shaft and guided thereby. The carriage includes a plurality of recording pens. The pen changer includes a frame and a shaft supported thereon. The carriage is supported on the shaft and guided thereby. The carriage includes a plurality of recording pens arranged along the axial direction of the shaft. The carriage moves essentially perpendicular to the paper. A hammer is axially movable on the shaft in response to movement of the carriage. A changing mechanism positions the hammer with respect to a selected one of the plurality of recording pens so the hammer can select the selected recording pen to plot on the paper.