A machining status monitoring apparatus is provided on a machine tool, and has a plurality of actual CCD cameras for imaging the tool and workpiece from different view points and generating actual two-dimensional image data thereof, a virtual image generating section having a plurality of virtual CCD cameras corresponding to the actual CCD cameras, in which the tool and workpiece of three-dimensional model are imaged by the virtual CCD cameras from each point and virtual two-dimensional image data thereof are generated, and a display control section for selecting one virtual CCD camera corresponding to the virtual two-dimensional image data in which the distal end of the tool is not hidden by the workpiece among the generated two-dimensional image data, and displaying the actual two-dimensional image data generated by the actual CCD camera corresponding to the selected virtual CCD camera on a display device.