To provide a display device and a display method capable of providing maximum advertising effect while conserving power.

A controlling PC 10 allows a display image to be shown on a representative display 20A and let the representative display 20A generate a pixel lighting map of the image display from the voltage application states measured thereby. The controlling PC 10 calculates anticipated power consumption, expressed in terms of a total lighting rate, on the basis of the generated pixel lighting map of the image display and determines the number of displays 20 to display the image on the basis of the calculated anticipated power consumption. The number of the displays 20 to display the image is a value obtained by multiplying the total number of the displays 20 and the total lighting rate and truncating decimal places, and is equal to the number of permanently active displays 20J if the value is less than the number of the permanently active displays 20J. The controlling PC 10 allows the determined number of the displays 20 to display the image.