1. A numerical control apparatus for controlling a drive unit for a machine tool making the processing by relatively moving a workpiece and a tool, comprising: read skip signal input means for commanding to skip execution of instructions up to a desired instruction in a processing program; read skip end instruction storing means for storing said desired instruction; and read skip means for skipping the execution of instructions until the same instruction as said instruction stored in said read skip end instruction storing means is commanded, if a read skip signal is input by said read skip signal input means.