An automatic zoom apparatus and method for playing dynamic images. The automatic zoom apparatus provides more dynamic images to a user by detecting a dynamic change of image signals to zoom and display a predetermined area where the dynamic change is detected. To this end, the automatic zoom apparatus for playing the dynamic images comprises a motion detector for, when a zoom function is requested to zoom predetermined image signals, detecting a motion based on a color change between frames extracted from the predetermined image signals. Also included is a motion area designator for designating a predetermined area including objects of the motion detected by the motion detector, as a motion area, and a zoom controller for performing a zoom function for zooming an image of the image signals of the motion area designated by the motion area designator. Thereby, the user can enjoy a more dynamic image such that television watching is not as monotonous.