PURPOSE: To make window display easy to observe without complicating software by arranging a complicated plane display capable of performing a transparent or translucent display state by overlapping, and providing a display control part for each plane display individually.

CONSTITUTION: A liquid crystal display device LCD is comprised by overlapping the LCDs 1-3. The LCDs 1-3 are driven with independent display control parts 1-3, respectively, and also, the plane displays LCD1-3 can display the transparent or translucent display states. Therefore, the display contents of the plane displays LCD2 and LCD3 located at the rearward can be observed through the plane display LCD1 at the front when the plane display LCD1 is set at the transparent state. At such a case, parallax is generated depending on a position observing from the front due to the thickness of the plane display, and also, the display content of the plane display at the rearward darkens a little. Thereby, it is possible to remarkably make display easy to observe without using complicated software.