To display on each display device an image of an appropriate part based on the positional relation of display devices in an image to be displayed even when a plurality of display devices are disorderly arranged.

A position detection sensor detects the position of a master display device and the position of a slave display device. The master display device specifies a master image area corresponding to a display area of the own device in the image to be displayed, and displays an image included in the master image area of the image to be displayed in the display area of the own device. The slave display device specifies a slave image area corresponding to the master image area based on the positional relation between the position of the master display device and the position of the slave display device detected by the position detection sensor, and displays an image of the slave image area in the image to be displayed in the display area of the own device.