A memory device, such as three dimension AND Flash memory, including a plurality of word line decoding circuit areas, a plurality of common power rails and a plurality of power drivers is provided. The word line decoding circuit areas are arranged in an array, and form a plurality of isolation areas, wherein each of the isolation areas is disposed between two adjacent word line decoding circuit areas. Each of the common power rails is disposed along the isolation areas. The power drivers respectively correspond to the word line decoding circuit areas. Each of the power drivers is disposed between each of the power driving circuit areas and each of the corresponding isolation areas, wherein each of the power drivers is configured to provide a common power to the word line decoding circuit areas.