Abstract: A CD changing device including a bottom disc that is moved back and forth in a slide groove by a projecting gear, a turntable disposed on the bottom disc to receive a CD, a limit rod provided on the bottom of the projecting gear carrying a spring, and a slide block on the limit rod. The slide groove has a left-biasing mouth and a right-biasing mouth. The case has a rack engaging a bottom gear, and the bottom disc has a teeth base facing the rack. The slide block prohibits the linear motion of the bottom disc from interfering with rotation of the turntable.