To provide a screen switching device for a numerical controller capable of promptly displaying required image data at a display device by a simple procedure.

This screen switching device for the numerical controller is provided with the display device 2, a controller main body 3 provided with a storage means 8 for storing the plural image data to be displayed at the display device 2 and an image selection means for selecting specified image data from the image data and an input device 4 for specifying a screen to be displayed at the display device 2. The image selection means directly selects the image data corresponding to the screen specified by the input device 4 from the storage means 8 and displays them at the display device 2.