A touchscreen sensor includes a transparent base material, a first transparent electrode pattern, a first index-matching layer and a first adhesive layer disposed in this order at one side of the transparent base material, and a second transparent electrode pattern, a second index-matching layer and a second adhesive layer disposed in this order at another side of the transparent base material. The first index-matching layer has a refractive index greater than a refractive index of the first adhesive layer. The second index-matching layer has a refractive index greater than a refractive index of the second adhesive layer. Each of the first index-matching layer and the second index-matching layer has a thickness of 85 nm to 120 nm.