1. A driving method of a plasma display device comprising: constituting one field period by a plurality of subfields having a predetermined luminance weight; selecting a plurality of combinations from arbitrary combinations of the subfields and creating a combination set for display; and controlling light emission or no light emission in a discharge cell and displaying gradation, using the combination of the subfields belonging to the combination set for display, wherein a plurality of combination sets for display having a different number of combinations is provided, wherein respective spatial differentiations of a red image signal, a green image signal, and a blue image signal are calculated, and wherein a combination set for display is used for an image signal of a large spatial differentiation, the number of combinations in the combination set for display being smaller than that in a combination set for display used for an image signal of a small spatial differentiation.