1. A method for inspecting a flat panel, the method comprising: arranging a camera at a measurement location of the flat panel by horizontally moving at least one of the flat panel and the camera; automatically focusing the camera on a target to be measured of the flat panel at the measurement location; acquiring a plurality of images of the target to be measured by vertically moving the focused camera within a set region based on the current location of the camera; selecting an image with the highest definition among the plurality of acquired images to process the selected image; and determining whether the target to be measured is defective or not.