A touch sensor comprising: a plurality of sensing electrodes, each sensing electrode comprising first electrode cells arranged in a first direction, a first connection portion connecting the first electrode cells in the first direction, wherein one of the first electrode cells includes a first opening; a plurality of noise detecting electrodes corresponding to the plurality of sensing electrodes, each noise detecting electrode comprising an electrode portion disposed in the first opening of a corresponding one of the plurality of sensing electrodes, the electrode portion being on a same layer (L1_5) as the first electrode cells and separated from the plurality of sensing electrodes, a plurality of sensing channels, each sensing channel comprising a first terminal connected to one of the plurality of sensing electrodes and a second terminal connected to the plurality of noise detecting electrodes, wherein each of the plurality of sensing channels is configured to generate an output signal corresponding to a voltage difference between the first terminal and the second terminal; a plurality of driving electrodes, each comprising second electrode cells arranged in a second direction crossing the first direction, and third connection portions connecting the second electrode cells in the second direction, wherein each driving electrode is separated from the plurality of sensing electrodes and the plurality of noise detecting electrodes; a driving circuit configured to supply a driving signal to the each of the plurality of driving electrodes; and a processor configured to: receive output signals from the plurality of sensing channels; and detect a touch input on the basis of the output signals; Characterised in that: the plurality of noise detecting electrodes are connected in common to a same third wire; and the second terminal of each sensing channel is connected to the plurality of noise detecting electrodes via the third wire. a plurality of sensing electrodes, each sensing electrode comprising first electrode cells arranged in a first direction, a first connection portion connecting the first electrode cells in the first direction, wherein one of the first electrode cells includes a first opening; a plurality of noise detecting electrodes corresponding to the plurality of sensing electrodes, each noise detecting electrode comprising an electrode portion disposed in the first opening of a corresponding one of the plurality of sensing electrodes, the electrode portion being on a same layer (L1_5) as the first electrode cells and separated from the plurality of sensing electrodes, a plurality of sensing channels, each sensing channel comprising a first terminal connected to one of the plurality of sensing electrodes and a second terminal connected to the plurality of noise detecting electrodes, wherein each of the plurality of sensing channels is configured to generate an output signal corresponding to a voltage difference between the first terminal and the second terminal; a plurality of driving electrodes, each comprising second electrode cells arranged in a second direction crossing the first direction, and third connection portions connecting the second electrode cells in the second direction, wherein each driving electrode is separated from the plurality of sensing electrodes and the plurality of noise detecting electrodes; a driving circuit configured to supply a driving signal to the each of the plurality of driving electrodes; and a processor configured to: receive output signals from the plurality of sensing channels; and detect a touch input on the basis of the output signals; receive output signals from the plurality of sensing channels; and detect a touch input on the basis of the output signals; the plurality of noise detecting electrodes are connected in common to a same third wire; and the second terminal of each sensing channel is connected to the plurality of noise detecting electrodes via the third wire.