To enable a work for confirming the relation between an actual object and an imaging means and a work for comparing the object with an image processing result, to thereby readily carry out the operation without the use of a monitor.

In an imaging section 1, a light-projecting section 11 includes a LCD 12, and is disposed as to be coaxial with a CCD 10, so that an image displayed on a LCD 12 can be projected toward a visual field of the CCD 10. In a processing section 2, a defect D in a workpiece W0 is detected, by using the image generated by the CCD 10 to generate a projection image 50, by setting an image data brighter than an ambience to an area RP corresponding to an area R, including the defect, provided to the projecting section 11, and projected. A range detected as the defect by image processing is defined by a marking pattern M by the projected image in the area RP among a surface of the workpiece W0 with regard to the projection.