To reliably prevent such a phenomenon that a display devoid of meaning which is not intended (waste display) appears at an instant when a power source is supplied.

The display device is provided with a drive part, a display part and a control part. The drive part has a power source terminal for memory, a memory for storing an information signal in the state that the power feeding of the power source terminal is held and a power source terminal for outputting display signal and, by using an electric power received via the power source terminal for outputting display signal, outputs the information signal stored in the memory as a display signal. The display part receives the display signal and displays the contents according to the display signal. After starting the power feeding to the power source terminal for memory, the control part writes the information signal of performing a desired display on the display part into the memory and, thereafter, the power is fed to the power source terminal for outputting display signal. That is, before the drive part outputs the display signal, the information signal of performing a desired display on the display part is written into the memory. As a result, such a phenomenon that a waste display appears at an instant when a power source is supplied is reliably prevented.