A graphic processor comprises an input device for inputting a command from an operator, a display device for displaying graphic data and a computer for preparing and correcting graphic data by a command input from the operator and for making display control of the display device. When the operator wants to know the content of the command that is executed, he instructs the command to the computer. A command name, a processing content and a figure as an object of processing are calculated from history data instructed from the computer. The figure as the object of processing, the command processing content and the relation of correspondence are symbolized and displayed on the display device. Furthermore, a parametric figure is also displayed visually on the display device.