To facilitate a stroke command operation when an image imaged by the image imaging section of a slave unit is displayed on the display section of a master unit.

When the image imaged by the image imaging section 12 of the slave unit 1a is displayed on the master unit display section 21 of the master unit 2a, the sensor light receiving section of the display screen 210 that the display section of the master unit has receives a reflected light with a finger by each display pixel as a surface sensor 211, and a master unit control section 22a analyzes the action of the finger based on the position information detected by the surface sensor. If the master unit control section detects the matching of the analyzed finger action and a predetermined pattern, it displays the image to be displayed on the display screen in a new image prepared corresponding to the pattern.