An array sensor is provided. The array sensor includes a sensing array, a memory array, and an access module. The sensing array includes a plurality of sensing units, wherein each of the sensing units includes a sensing electrode. The memory array includes a plurality of memory units, wherein each of the memory units is disposed below the corresponding sensing unit or between the two adjacent sensing units. The access module selectively reads a sensing value of the sensing electrode of the sensing unit to provide a sensing output, or accesses the memory unit.