Provided are a contents generating apparatus that can support functions of moving object substitution, depth-based object insertion, background image substitution, and view offering upon a user request and provide realistic image by applying lighting information applied to a real image to computer graphics object when a real image is composited with computer graphics object, and a contents generating method thereof. The apparatus includes: a preprocessing block, a camera calibration block, a scene model generating block, an object extracting/tracing block, a real image/computer graphics object compositing block, an image generating block, and the user interface block. The present invention can provide diverse production methods such as testing for the optimal camera viewpoint and scenic structure before contents are actually authored and compositing two different scenes taken in different places into one scene based on a concept of a three-dimensional virtual studio in the respect of a contents producer.