PURPOSE: To enable flexible correspondence and to exactly input data without making a display screen dirty at the input device used for the data input of a numerical controller, etc.

CONSTITUTION: Input data, parameters previously inputted before operating the numerical controller, for example, pitch error correcting amount and machine tool correcting amount or the like are displayed in respective display areas A-T on a display screen 27a. When an operator lightly pushes a touch area (g) of a touch panel 28 with a finger 40, the display area G corresponding to the pushed touch area (g) is displayed in a color different from that of the other areas, for example, only the area G is displayed in blue when the other areas are displayed in white. When it is desired to select the input data in this display area G, the operator strongly pushes the touch area (g). Thus, the display area G is displayed in red, for example.