A numerical control system for a machine tool includes a display screen, a storage unit, and a control unit. The control unit executes a step of displaying, on the display screen, a designation screen that selects and designates one or more pieces of auxiliary information and auxiliary functions corresponding to each of basic work screens prepared for each work process using the machine tool, and associating with the basic work screen and storing in the storage unit one or more pieces of auxiliary information and auxiliary functions selected and designated by a user through the designation screen, and a step of simultaneously displaying, on the display screen, one basic work screen designated by the user among the basic work screens, and one or more virtual buttons that select one or more pieces of auxiliary information and one or more auxiliary functions, associated with the user-designated basic work screen.