A touch sensor configured to sense a touch object is provided. The touch sensor includes a sensing device and a sensing circuit. The sensing device includes a substrate, a sensing electrode, a sensing common electrode and a shielding layer. The sensing electrode and the sensing common electrode are disposed on the substrate. The shielding layer is disposed on the sensing electrode and the sensing common electrode. The sensing circuit is electrically connected to the sensing device. The sensing circuit includes a resistor device. A relaxation frequency of a relaxation signal of the touch sensor is determined according to a resistance of the resistor device and/or a parasitic resistance of the sensing device. A pulse difference of the relaxation signal is changed by the touch object. The touch object is a conductor. An electronic paper display panel including the foregoing touch sensor is also provided.