Workpiece inspecting apparatus and workpiece inspecting method

A workpiece inspecting apparatus for rotating a workpiece having a shape portion containing a convex portion and a concave portion which are periodically and repetitively formed on the workpiece and picking up images of the shape portion of the workpiece to inspect the workpiece, comprising:

• a workpiece rotating mechanism that outputs reference pulses at a fixed interval while rotating the workpiece at a fixed rotational speed;
• an image pickup mechanism that picks up images of the shape portions of the workpiece every image pickup timing based on the reference pulses;
• an image pickup controller that synchronizes each of the shape portions of the workpiece with the image pickup timing based on the reference pulses;
• and
• an inspection processor that executes first image processing of taking a difference between a pickup k-th (k represents an integer) image and a pickup (k+1)-th image and first inspecting processing of detecting a defect on the basis of differential data representing the difference.