Provided is a head up display (HUD) apparatus for realizing multi-display field and a display control method thereof. The HUD apparatus includes a first image processing unit allowing a virtual image, corresponding to driving information or vehicle information generated from a first image source, to be displayed on a main display field and a second image processing unit allowing a virtual image, corresponding to at least one of driving information, image information, and vehicle information generated from a second image source, to be displayed on a sub display field.