To provide an automatic boring apparatus using a plurality of NC drill machines, capable of performing centralized control and centralized monitoring to enable a user to perform boring machining using a plurality of NC drill machines by oneself.

In positioning a work origin, an origin detecting camera 6 is mounted on a machine head 4 of each NC drill machine 1, an origin mark is automatically detected by image processing to automatically set the origin of the work 5 to an NC control board 3. Further, a monitoring camera 17 for photographing a machining area of each NC drill machine is provided and the photographed image is displayed on a supervisory monitor 18, whereby the origin detecting camera 6 can be easily guided to the vicinity of the origin position by manual work, and the plurality of the supervisory monitors 18 for displaying the images of the monitoring cameras 17 mounted on each NC drill machine 1 at the same time are installed on the centralized control device 10 to thereby monitor the operating status of the plurality of machines.