1. A wafer image inspection apparatus for obtaining and inspecting an image of a semiconductor wafer so as to inspect a defect in the wafer, the wafer image inspection apparatus comprising: a lighting unit which generates lighting, a lens unit which obtains an image of a target inspection wafer reflected after the lighting is radiated to the wafer and projects and transfers the image in one direction, an image detection unit which comprises a split optical element for splitting the image of the wafer transferred by the lens unit and a plurality of image pick-up elements installed so that an image passing through the lens unit and the split optical element is formed on different focal positions, and a through focus scanning optical microscopy (TSOM) image processing unit which forms a TSOM image by combining the images of the different focal positions captured by the plurality of image pick-up elements and determines whether the target inspection wafer has a defect by comparing the TSOM image with a TSOM image of a normal pattern for the target inspection wafer.