A control device for a machine tool, said control device being provided with a display unit that displays machining information and a display control unit that generates an image to display on said display unit. The display control unit is designed so as to divide up the display region of the display unit, generating a plurality of subregions. Via input from an operator, the sizes of said subregions can be changed. The display control unit changes the display format of the machining information in accordance with the machining information to be displayed and the sizes of the subregions.