A display driving method drives a display to make a gradation display on a screen of the display depending on a length of a light emission time in each of sub fields forming 1 field, where 1 field is a time in which an image is displayed, N sub fields SF1 through SFN form 1 field, and each sub field includes an address display-time in which a wall charge is formed with respect to all pixels which are to emit light within the sub field and a sustain time which is equal to the light emission time and determines a luminance level. The display driving method includes the steps of setting the sustain times of each of the sub fields approximately constant within 1 field, and displaying image data on the display using N+1 gradation levels from a luminance level 0 to a luminance level N.