An image distortion correcting apparatus is provided tat is capable of correcting keystone distortion and pincushion distortion in a video display device. The apparatus may include a reference image generating device for generating a reference image and setting a coordinate of the reference image. A displacement measuring device may display the reference image on a screen and measure a coordinate of the displayed image. A distortion information extracting device may extract distortion information on the basis of a coordinate value of the set reference image and a coordinate value of the measured image and generating inverse-distortion information. Still further, a distortion correcting device may generate an inverse-distorted (pre-warping) image of the reference image on the basis of the generated inverse-distortion information.