A CRT displaying method for use in a numerical control device for controlling a machining apparatus which is provided with a machining tool to machine a workpiece, for example a wire electric discharge machining apparatus. When an error condition occurs, an alarm code number corresponding to the error condition is displayed together with an alarm message corresponding to the alarm code number. Further, a manner how to escape from the error condition is obtained based on the alarm code number and an operational program so that an operator can move the machining tool easily to escape from the error condition according to the manner which is displayed on the CRT graphical and literally.