PURPOSE: To securely prevent the occurrence of an unnecessary picture which is not intended by providing a switching means which operates by the depression of a frame body provided at the outer peripheral part of a plotting part and operating a processing part and a display part only while the switching means is operated.

CONSTITUTION: The frame body 15 provided at the outer peripheral part of the plotting part 13 and the switching means 21 operating by the depression of the frame body 15 are given. The processing part and the display part are operated only while the switching means 21 is operated. Namely, a plotting device is constituted in such a way that a coil spring 19 is embedded in the case 3 positioned at the lower side of the frame body 15, the lower end part of the frame body 15 is held in a state where it is slightly floated from the case 3 by the repulsive force of the coil spring 19 and a switch 21 operates when the frame body 15 is pressed down against the repulsive force of the coil spring 19. Thus, the processing part and the display part are prevented from operating even if a hand is brought into contact with the plotting part 13 in a state where the frame body 15 is not depressed. Thus, the occurrence of the unnecessary picture which is not intended can securely be prevented.