A method for manufacturing a touch sensor having a single ITO layer is disclosed by the invention, including steps of: a) performing cleaning processing on a glass substrate; b) forming an index matching layer on the glass substrate, portions of the index matching layer corresponding to sensor cutting marks and sensor binding regions being at least partially removed, via a peelable adhesive disposed at sites corresponding to the sensor cutting marks and the sensor binding regions on the glass substrate or the index matching layer; c) forming an ITO layer on the partially removed index matching layer; and d) etching the ITO layer so as to form an pattern of the single ITO layer of the touch sensor. A touch sensor having a single ITO layer manufactured by the method and a touch screen including the touch sensor are further disclosed by the invention.