A main unit (television receiver) displays a television broadcasting program and also detects its feature. In addition, the main unit detects a scene change from the feature of the television broadcasting program, and controls a subsidiary unit (television receiver) so as to display the image data of the frame immediately after the scene change. The subsidiary unit displays the frame immediately after the scene change. Then, when another scene change occurs in image data displayed on the main unit, the image data of the frame immediately after the scene change is displayed on the subsidiary unit, instead of the image data which has been displayed so far.