A numerical controller provided with a function of registration and management of an application and capable of coping with a case in which necessary operation is changed in accordance with a situation, includes an application manager which registers the application to an operation process and manages an operation state and the present operation process among the operation process, and a menu display application which executes display control of a screen based on the operation state of the application acquired from the application manager. The application manager outputs a notification of start of the operation process to the application when the operation process is started, instructs the menu display application to emphasize and display the application when receiving a notification of a request of input of a user from the application, and advances the operation to the next operation process when all applications registered to the present operation process are completed.

A control device controls display of a display device for displaying a display screen for setting operations of the control device that controls an industrial machine and soft keys for operating the display screen. The control device includes: a key input processing unit that receives input from an input device; an input content determining unit that determines a content of the input received by the key input processing unit; a storage unit that stores a soft key definition information table in which operation contents on the display screen to be allocated to the soft keys are defined in advance; a soft key allocation selecting unit that selects the operation contents to be allocated to the soft keys; and a soft key display processing unit that displays the soft keys allocated with the operation contents selected by the soft key allocation selecting unit on the display device.

A control device controls display of a display device for displaying a display screen for setting operations of the control device that controls an industrial machine and soft keys for operating the display screen. The control device includes: a key input processing unit that receives input from an input device; an input content determining unit that determines a content of the input received by the key input processing unit; a storage unit that stores a soft key definition information table in which operation contents on the display screen to be allocated to the soft keys are defined in advance; a soft key allocation selecting unit that selects the operation contents to be allocated to the soft keys; and a soft key display processing unit that displays the soft keys allocated with the operation contents selected by the soft key allocation selecting unit on the display device.

An operation panel for operating a machine tool includes a first display unit for displaying information related to the machine tool, a keyboard, and a plurality of buttons. The button includes a second display unit and a transparent cover. The second display unit displays a first key image indicating a first function and is able to be switched to display a second key image indicating a second function depending on an application screen displayed on the first display unit.