Abstract: An active device array substrate including a substrate, an active device array, pad sets, connecting lines, and switch devices is provided. The substrate has a display region and a peripheral circuit region, and the active device array is disposed on the display region. The pad sets are disposed on the peripheral circuit region and electrically connected to one other. Each pad set has a plurality of pads, and a portion of the pads is electrically connected to the active device array. The connecting lines are disposed on the peripheral circuit region, and the pad sets are electrically connected to each other by the connecting lines. The switch devices are disposed on the peripheral circuit region, and at least one of the switch devices is disposed between adjacent pads in each pad sets. Further, each switch device is electrically connected to the adjacent pads.